PAULING, LINUS CARL

(b. Portland, Oregon, 28 February 1901; d. Big Sur, California, 19 August 1994), chemistry, quantum chemistry, nature of the chemical bond, x-ray crystallography and molecular structure, biochemistry and molecular biology, molecular medicine.

Often called the Einstein of chemistry, Pauling is widely regarded as the most important chemist of the twentieth century. Best known for his foundational work in theoretical chemistry, and in biochemistry and molecular biology, he played a formative role in at least five major developments in twentieth-century science: the application of quantum physics to chemistry; the use of theories of chemical structure in biology; the construction of molecular models that became a characteristic tool of modern chemistry; the study of diseases as a product of molecular processes; and the role of scientist as public citizen and political activist. Pauling received the Nobel Prize in Chemistry for 1954 and the Nobel Peace Prize for 1962. He is the only individual to receive two unshared Nobel awards.

Early Life and Education Pauling was born in Portland, Oregon. His father, Herman Henry William Pauling, was a pharmacist who moved to Condon in eastern Oregon, and young Linus watched his father make extracts and salves, measure and mix powders, and test solutions with litmus papers. Among the boy’s early reading were his father’s pharmacopoeia and dispensatory, along with the Bible and Charles Darwin’s Origin of Species. His father died suddenly of a perforated stomach ulcer in June 1910, and Pauling’s mother Lucy Isabelle moved Linus and his two younger sisters back to Portland, where Belle took boarders into their house. Linus attended Washington High School, where his coursework included general sciences, chemistry, and physics. He failed to complete the American history requirement because of a scheduling conflict, and he entered Oregon Agricultural College (later Oregon State University) in Corvallis without a diploma in 1917.

At that time the college in Corvallis was one of the nation’s largest land-grant institutions, with four thousand students and two hundred instructors. Pauling quickly attracted the attention of his teachers in his chemical engineering major, and they enlisted him to teach freshman-and sophomore-level chemistry courses while he was still a student. As he prepared his chemistry lectures in 1920, Pauling ran across Irving Langmuir’s articles in the 1919 Journal of American Chemistry on the structure of atoms and the electron theory of the valence bond. Langmuir’s publications led Pauling back to the 1916 paper of Gilbert Newton Lewis, whom he revered for the rest of his life. In this paper Lewis proposed the electron pair as the fundamental chemical bond, with the loss or capture of electrons accounting for chemical reactivity when an atom tends to achieve the two-electron or eight-electron structure of an inert gas. From 1920 on, Pauling rarely had the chemical bond far from his mind. Nor did he relinquish the fascination with molecular form and structure that first engaged him in a course in Corvallis with Samuel Graf on the crystallography of metals. The chemical bond and molecular structure became permanent leitmotifs for Pauling’s chemical career.

Pauling was ambitious early on. He applied unsuccessfully for a Rhodes Scholarship and, like others of his twelve classmates in chemical engineering, he applied to graduate school. Six of the twelve completed their PhDs, including Paul Emmett, who married Pauling’s sister Pauline. In the fall of 1922 Pauling and Emmett both entered the California Institute of Technology (Caltech), where Arthur Amos Noyes headed the chemistry department.

During the summer before graduate school, Pauling worked for the Oregon Highway Department near Astoria. By then, he had proposed marriage to Ava Helen Miller (1903–1981), a student in Chemistry for Home Economics Majors, a class he had taught the previous spring. Pauling’s summer letters to Ava Helen give insights into his aims and ambitions, which, he wrote, included not only a PhD but also a Nobel Prize. Ava Helen and Linus were the closest of companions following their marriage in June 1923, and she played an important role in his later political activism. It was her influence that led him to change his registration in 1934 from the Republican to the Democratic Party, and they worked closely together in the campaign of the 1950s for a ban on nuclear testing. The first of their four children, Linus Carl Pauling Jr., was born in 1925, followed by Peter Jeffress Pauling (b. 1931), Linda Helen Pauling (b. 1932), and Edward Crellin Pauling (1937–1997).

After arriving at Caltech in fall 1922, Pauling’s coursework included thermodynamic chemistry with Noyes, statistical mechanics and atomic structure with Richard Chace Tolman, kinetic theory with Robert Millikan, advanced dynamics with Arnold Sommerfeld’s student Paul Epstein, and statistical mechanics and quantum theory with the visiting Austrian theoretical physicist Paul Ehrenfest. Pauling’s first paper, on the structure of the mineral molybdenite (MoS₂), appeared in 1923. It was coauthored with Roscoe G. Dickinson, his research supervisor in x-ray crystallography. In the next three years, Pauling authored or coauthored a dozen crystal-structure publications, completing his PhD in 1925 with the dissertation “The Determination with X-Rays of the Structure of Crystals.” In 1928 Pauling developed systematic rules governing the geometry of the coordination polyhedron of negative ions around a positive ion in an ionic crystal, enabling him to solve the structures of silicates such as mica, talc, and topaz. The work on silicates gained him his first international recognition.

Pauling’s 1926 application for a Guggenheim Foundation Fellowship focused on something different, however. Pauling expressed the aim to take up the programmatic goal expressed by Sommerfeld for working out a topology of the interior of the atom and a system of mathematical chemistry that would detail the exact position of electrons and explain the formation of molecules and chemical compounds. Embarking on a physicist-inspired reductionist program for chemistry during his first trip to Europe, Pauling spent a year with Sommerfeld in Munich, a month in Copenhagen with Niels Bohr, and six months in Zürich with Erwin Schrödinger, whose electron wave theory and equation had just appeared in 1926.

While in Zürich, Pauling met Fritz London and Walter Heitler, who were working out a valence bond (atomic orbital or AO) treatment of the electron bond in the hydrogen molecule, which they published in 1927 using Werner Heisenberg’s new notion of exchange or resonance energy arising from the interchange of two electrons with opposite spin. About the same time, in Göttingen, Friedrich Hund was developing a molecular orbital approach (MO), generalizing recent work by the Danish physicist Oyvind Burrau. The AO approach treats the hydrogen molecule as two hydrogen nuclei with the wave function of each electron centered on one of the nuclei and electrons tending to aggregate in the region between the two protons. In contrast, the MO theory assumes that any one electron moves in a potential field that results from all the nuclei and other electrons together. The AO method exaggerates the covalent character of chemical bonds, and the MO method the ionic character. In the long run, Pauling was to become a champion of the AO theory, and Robert S. Mulliken, who met Hund in Göttingen, became an outspoken advocate in the United States of the MO theory.

Pauling became an assistant professor of theoretical chemistry when he returned to Caltech in late 1927. He corresponded and collaborated with Samuel Goudsmit, whom he had met in Copenhagen, on an expansion and English translation of Goudsmit’s Leiden doctoral thesis under Ehrenfest, into a book The Structure of Line Spectra, which appeared in 1930. While working on the structure of silicates, Pauling also published an explanation in Chemical Reviews of the AO and MO theories that he had learned in Germany, and he began to sketch out his own ideas for a theoretical treatment of the chemical bonds in methane, which, as a chemist, he considered the most crucial molecule after hydrogen.

The Chemical Bond and Quantum Chemistry Methane is composed of one atom of carbon and four atoms of hydrogen. The carbon atom has six electrons, which should be distributed on the basis of quantum principles into energy states of 1s², 2s², 2p². Carbon has four valence electrons, however, and they are identical in their energy states. Pauling’s notion was to do away with a distinction between 2s and 2p energy sublevels in favor of four mixed levels or orbitals of the same energy value. From 1929 to 1934 Pauling presented these ideas to advanced students and faculty in Lewis’s chemistry department at Berkeley, where he shared his time in teaching with Caltech. In these lectures Pauling presented his notion of mixed or “changed quantization” (later called hybridization) of electron energy levels, setting up quantum wave functions to represent valence, or electron-pair, bonds, in carbon compounds. In 1931 Pauling (and, independently, John Slater at Harvard University) demonstrated that wave functions project out in characteristic directions: p-level energy waves, for example, are represented by three dumbbell-shaped distributions or contour-lines at right angles to one another, whereas the s-level wave is a spherically shaped distribution. Pauling extended this treatment to other kinds of bonds, for example, double and triple bonds using trigonal and digonal mixed orbitals. Energy data from thermochemistry and from spectroscopy provided solutions to calculations of the bond energies, while information from x-ray crystallography about bond angles and interatomic distances further grounded the theory in chemical and physical facts. Pauling also developed a scale or table of atomic electronegativities for the chemical elements that predicted the energy and electric dipole moment, or ionic character, of any type of bond.

Among the most puzzling molecular structures that had been studied since the nineteenth century were conjugated molecules of alternating single and double bonds, including aromatic compounds such as benzene. Benzene resisted representation by any one structural formula, and its conflicting structures came to be identified with the names of August Kekulé and James Dewar in the late nineteenth century. In the 1920s and 1930s Pauling’s Caltech colleague Howard J. Lucas, along with the British chemist Christopher Ingold and the German chemist Fritz Arndt, were among those who proposed that the real structure for a conjugated molecule such as benzene may be one single structure that is different from any of the familiar valence-bond structures that had been used simultaneously and interchangeably. Arndt used the term Zwischenstufe for this nonvisualizable real structure and Ingold coined the word mesomer.

Collaborating with George Willard Wheland, Pauling explained aromatic structure as another instance of resonance or the behavior of wave functions in quantum mechanical exchange phenomena. Their paper was one of a series of seven papers written or coauthored by Pauling (with Wheland or Albert Sherman) that appeared from 1931 to 1933 under the title “The Nature of the Chemical Bond” in the Journal of the American Chemical Society and the Journal of Chemical Physics. Pauling followed up these papers by enlisting Edgar Bright Wilson Jr. to help write the rigorously mathematical Introduction to Quantum Mechanics, with Applications to Chemistry. The 1935 book’s claims are modest but profound: All the chemical properties of atoms and molecules are explicable in terms of the laws and equations governing the motions of the electrons and nuclei composing them.

In 1939 Pauling revised the earlier papers on the chemical bond into a series of lectures at Cornell University. The manuscript became his classic textbook, The Nature of the Chemical Bond and the Structure of Molecules and Crystals. It was a textbook that changed the way scientists thought about chemistry, presenting chemistry as a discipline unified by an underlying theory. By demonstrating how the characteristics of the chemical bond determine the structure of molecules and how the structure of molecules determine their properties, Pauling showed for the first time, as the Austrian-born British biochemist Max Perutz later said, that chemistry could be understood rather than simply memorized. Fifty years later, in 1989, The Nature of the Chemical Bond still ranked among the top five most-cited books in the Institute for Scientific Information database.

The valence-bond atomic-orbital theory shared theoretical territory with an increasingly powerful MO theory in the long run. Pauling’s AO approach, well-grounded in traditional chemical theory of the nineteenth century and in Lewis’s hypothesis of the electron-valence bond, earned most chemists’ allegiance until the 1950s and 1960s, when MO methods became more widespread, partly as the result of developments in molecular spectroscopy and in electronic computers, and partly through the influence of English theoretical chemist Charles Alfred Coulson, whose book championing MO theory, Valence, first appeared in 1952. Pauling himself always preferred the valence-bond AO approach, but quantitatively-minded quantum chemists came to prefer the convenience of calculation of the MO approach, especially for large molecules.

Molecular Structure, Biology, and Medicine Pauling became professor at Caltech in 1931, the year that he received the American Chemical Society’s first Langmuir Prize for the most promising young chemist in the country. In 1933 Pauling became the youngest member ever elected to the National Academy of Sciences. He was appointed director of the Gates Laboratory and chairman of the Division of Chemistry and Chemical Engineering at Caltech in 1937, following the death of Noyes. Like many chemists in the 1930s, Pauling found himself in a university-level institution in which biology and medicine increasingly were gaining prominence in teaching and research. After Thomas Hunt Morgan organized a biology division at Caltech in 1928, Pauling began to participate in biology seminars on campus, and in 1931 some of the Caltech biologists invited Pauling to give a seminar on a German article about a mathematical theory of crossing over in chromosomes. His reading in biology began to affect his thinking about chemistry, including his adoption of the term hybridization to describe the “changed quantization” of the chemical bond.

Biologically significant compounds such as urea, oxamide, and oxamic acid were among the compounds that Pauling and his associates investigated in the 1930s from the standpoint of thermodynamics, bond configurations, and resonance structure in the amide group. The nucleic acid bases guanine and purine were among the compounds for which Sherman and Pauling calculated resonance energy in 1933. Pauling’s visit to Hermann Mark’s Berlin laboratory in 1930 familiarized Pauling with Mark’s use of x-ray diffraction data in the study of proteins and with Mark’s and Kurt Meyer’s ideas on the structure of proteins whereby long and flexible polypep-tide chains are attracted to one another by forces between the C=O groups and the NH groups on adjunct chains. Pauling himself turned in 1932 to the structures of proteins, including hemoglobin and other molecules of medical interest.

A shift in emphasis toward a biological program at the Rockefeller Foundation, which had been funding Pauling’s work in chemistry, offered support for his investigations in biochemistry. This biologically oriented research included a 1935 paper on the shape of the oxygen equilibrium curve for the protein hemoglobin and an investigation in 1936 with Charles Coryell of the magnetic properties of a hemoglobin molecule. In another paper, written with Alfred Mirsky from the Rockefeller Institute, Pauling proposed a coiled, or folded, structure for the protein keratin, arguing, like Mark and Meyer, for the molecular structure of proteins at a time when the colloidal theory of proteins was not yet dead. In 1939 Pauling wrote a controversial paper with Carl Niemann discrediting Dorothy Wrinch’s cyclol theory of a symmetrical geometry in protein structure.

Correlating his interest in molecular structure or shape with an emerging focus on biological function, Pauling tried to answer a question posed to him by Karl Landsteiner at the Rockefeller Institute in 1936: could the properties of antibodies and antigens be a result of molecular structure? In 1940 Pauling proposed that polypeptide chains might fold and wind around the exterior of an antigen structure, creating an antibody that is complementary in structure to the invading antigen, similar to a lock-andkey (a metaphor used by the German protein chemist Emil Fischer in 1894 for an enzyme and its substrate). After discussing with his Caltech colleague Max Delbrück the need to explain the duplication of the antibody form, they collaborated in a note to Science on a speculation that biological replication likely is a matter of complementary shapes.

Another example of the usefulness of the hypothesis of complementary molecular shapes came in Pauling’s work with Harvey Itano on sickle-cell anemia in the late 1940s. Using electrophoresis, Itano discovered in 1949 that a sickle-cell individual’s hemoglobin has more positive charge on its surface than normal hemoglobin. Pauling proposed that this alteration in surface charge created an area complementary in shape to neighboring hemoglobin, like antigen and antibody. The molecules stick together, twisting the red blood cells out of shape into sickles rather than flat disks and clogging small blood vessels in the body. Pauling coined the term molecular disease.

During the early 1940s, Pauling’s systematic research program was interrupted by two events: illness and war. In 1941 he fell ill with a serious form of Bright’s disease, an often fatal kidney disease. His grandfather Linus Darling had died of kidney disease. For the next fifteen years Pauling followed a diet advocated by Dr. Thomas Addis of Stanford University, which stressed a low protein, salt-free diet with lots of water, and he improved remarkably after only six months.

At this time he already was at work at Caltech on military-related projects following a meeting in Washington, D.C., in October 1940, at which military officers presented chemical researchers with a list of needed breakthroughs in medicines, explosives, and monitoring and detection devices. Pauling immediately went to work on an oxygen meter for monitoring the air in submarines, and he arranged its production with Arnold Beckman, who had left teaching chemistry at Caltech to establish a scientific instruments business. Money flowed to Caltech during the war, and Pauling traveled once per month to Washington for meetings, making a three-day train trip each way. Pauling directed research projects at Caltech on rocket propellants and explosives powders. He headed a team for the synthesis of artificial plasmas that enlisted the expertise of Addis and the immunology expert Dan Campbell. Pauling also continued work, which had begun before the war with Campbell, on the synthesis of artificial antibodies. When J. Robert Oppenheimer asked Pauling in early 1943 to join the Manhattan Project at Los Alamos as head of the chemistry division, Pauling declined, preferring to remain at Caltech. In 1948 he received the Presidential Medal for Merit for his war-related work.

Pauling’s government and Rockefeller Foundation– sponsored research during the war years kept him focused on hemoglobin, immunology, and proteins along with other projects. Protein research was one of the major areas of study in x-ray crystallography and biochemistry, with British x-ray crystallographers such as John Desmond Bernal, Dorothy Hodgkin, and William Astbury among the pioneers in the field. While visiting Oxford in 1948 and confined with the flu, Pauling started building protein models, constructing a three-dimensional model of keratin as a spiral molecular structure using paper, ruler, and pencil to sketch out a chain of amino acids, and drawing the atomic-bond lengths and angles from memory. He realized, however, that an x-ray pattern produced from his model would not match the x-ray patterns that Astbury had published. After his return to Caltech, Pauling set to work with Herman Branson and Robert Corey to come up with an accurate model. In 1950 he and Corey published two structures for keratin, using hydrogen bonding for a coiled peptide chain. Their alpha-helix model had 3.7 amino acid residues per turn and called for a diffraction pattern showing about 5.4 angstroms between each turn, not quite on target with Astbury’s value of 5.1 angstroms. The fiber manufacturing firm of Courtaulds in London soon confirmed the alpha-helix in its commercial synthesis of artificial fiber similar to natural keratin, as did Perutz in later studies of natural keratin in the form of horsehair. In May 1951 Pauling and his coworkers published seven papers on protein structures in one issue of the Proceedings of the National Academy of Sciences(PNAS), including the alpha helix, parallel and antiparallel pleated sheets, and a winding three-helix model for the protein collagen.

Pauling’s method of modeling structures employed not only paper and pencil but wooden and plastic models constructed in Caltech’s chemistry shop. In the fall of 1938 Pauling had initiated correspondence with Joseph Hirschfelder at the University of Wisconsin about the usefulness of three-dimensional molecular models for teaching and research. The German chemist Herbert Arthur Stuart had designed “space-filling” models in 1934. In this type of model, spherical atom units are brought into contact with each other in diameters roughly proportional to van der Waals radii (the estimated atomic radius for a hard atom sphere). By 1939 the Fisher Scientific Company was selling kits of the space-filling models, while technicians at Caltech continued making models locally that were designed by Pauling, Verner Schomaker, and James Holmes Sturdivant. In the late 1940s the design and combination of atoms in these molecules used data about atomic sizes and interatomic distances and bond angles from x-ray spectrography, electron diffraction, and an electrical Fourier synthesizer.

Following his success with protein, Pauling began to apply his methods for uncovering molecular architecture to deoxyribonucleic acid (DNA), the molecule that the Rockefeller Institute bacteriologist Oswald Avery identified in 1944 as the transforming principle or material that transferred genetic traits between Pneumococcus bacteria. Most biochemists and biologists had assumed that protein is the principal material of the gene, but because DNA is the most common form of nucleic acid in chromosomes, Avery’s findings directed attention to the possible significance of DNA. A protein is a more complex molecule than DNA, and protein seemed the most likely candidate for the complexity of a genetic carrier. Protein consists of polypeptide chains of amino acids, of which twenty different ones are available for combinations within protein. In contrast, DNA contains only four nucleotides, each consisting of a sugar attached to a phosphate group and to one of four organic nitrogenous bases.

In February 1953 Pauling and Corey published a paper modeling DNA with three polynucleotide intertwined chains and with negatively charged phosphates at the core and nitrogenous bases on the outside. They based their structure on what turned out to be a misleading photograph made by Astbury in 1947 of what in fact was a mixture of two forms of DNA. The Astbury photograph resulted in calculation of an inaccurate figure for the density of the DNA molecule. Pauling did not try to make x-ray photographs himself, nor did he build a three-dimensional model before publishing his three-chain structure in 1953, nor did he focus on DNA as the possible genetic material. At the time, Pauling knew that Maurice Wilkins was working on DNA at King’s College and that Wilkins had some unpublished DNA photographs, but Wilkins had declined to share them when Pauling wrote him in the summer of 1951. Pauling did not contact Wilkins again when Pauling was in England in the summer of 1952.

In April 1953, Wilkins’s laboratory had new photographs of the dry and hydrated forms of DNA that had been made by Rosalind Franklin. Wilkins showed Franklin’s picture of the pure beta (extended and hydrated) DNA to James Watson and Francis Crick, who were working in the Cavendish Laboratory of William Lawrence Bragg, one of the founders and masters of x-ray crystallography. Watson and Crick immediately published a structure for DNA: two helical chains, each coiled round the same axis, with bases on the inside of the helix and phosphates on the outside. Franklin herself earlier had told them, when they were toying with a three-strand model, that the phosphates must be on the outside. All this was detailed by Watson himself in his popular but controversial book The Double Helix, published in 1968.

Watson, a young microbiologist, had worked with Delbrück for a few months in 1949 in Pasadena and stayed in touch with him. More significantly, Pauling’s son Peter, who was sharing an office at the Cavendish Laboratory with Watson and Crick in 1953, showed them a copy of his father and Corey’s prepublication paper with the three-strand model of DNA, precipitating what Watson and Crick later described as their mad pursuit to beat Pauling to the prize. In their work Watson and Crick self-consciously and successfully used Pauling’s method of model building. Their paper in Nature explicitly contrasted their double helix model with Pauling’s triple helix model and noted the implications of the two-strand model for genetic replication. Pauling was gracious about his missed discovery, later expressing puzzlement that he had ignored his earlier idea published with Delbrück in 1940 that genetic material might consist of two complementary molecules.

Nuclear Weapons and Political Activism In 1954 Pauling received the Nobel Prize in Chemistry for his research into the nature of the chemical bond and its application to the elucidation of the structure of complex substances. The award came at a time when his work on proteins and DNA was getting much welcome attention, in contrast to the unwelcome attention paid his political activities. Following the war, Pauling joined several organizations concerned with atomic-science issues, including the Emergency Committee of Atomic Scientists, chaired by Albert Einstein, whom Pauling had first met in Pasadena in 1932. Pauling’s criticism of U.S. nuclear policy included worries about the Truman administration’s talk of a first nuclear strike against the Soviet Union. Pauling and Ava Helen joined the Independent Citizens’ Committee for the Arts, Sciences, and Professions (ICCASP), a left-wing organization of Los Angeles–area artists and intellectuals, which came under scrutiny from the House Un-American Activities Committee in 1947. In 1948 Federal Bureau of Investigation agents investigated Pauling for Communist sympathies, and in November 1950 he was called to testify before the California Senate Investigating Committee on Education, where he defended his objection to loyalty oaths. Under criticism for his political views from Caltech trustees, he began losing consulting contracts, committee appointments, and speaking engagements, and he was denied a passport in early 1952, preventing him from attending a spring Royal Society discussion on proteins. Ironically, Pauling was an object of denunciation by the Chemists’ Division in the Soviet

Academy of Sciences in the summer of 1951 on the grounds that his chemical resonance theory was an idealistic, antimaterialistic, and bourgeois invention.

Following his trip to Stockholm to receive the Nobel chemistry prize in December 1954, Linus and Ava Helen Pauling visited Israel, India, Thailand, and Japan, arriving in Japan in February 1955, when the crew of the Lucky Dragon still was under observation following the U.S. explosion of thermonuclear devices over Bikini Atoll the previous spring. In July 1955 he joined more than fifty other Nobel laureates in issuing the Mainau Declaration, which called for an end to all war, especially nuclear war. Pauling also entered a long-running scientific debate over the biological effects of chronic, low-level radiation from atmospheric nuclear tests, connecting the problem of possible genetic damage to his knowledge of DNA and nucleic acids as carriers of inherited characteristics.

In 1958 and 1959 Pauling wrote papers, one of them with his future son-in-law Barclay Kamb, on the probabilities of genetic mutations from radionuclides in atmospheric fallout, concentrating on⁹⁰Sr, which the U.S. Atomic Energy Commission (AEC) had previously been studying, and¹⁴C, which had not been considered to pose a possible hazard. In opposition to optimistic reports from the AEC and scientists such as Willard Frank Libby, Edward Teller, and Miriam Finkel that radioactive isotopes in fallout were unlikely to cause genetic or somatic effects, Pauling adopted the linear hypothesis of Edward B. Lewis, his Caltech colleague in genetics, that even minimum levels of radiation are cumulative in effect and can cause cell damage. A live debate between Teller and Pauling aired on public television in San Francisco in February 1958.

In May 1957, following a visit to Washington University in St. Louis, Pauling joined with the biologist Barry Commoner and the physicist Edward Condon in writing an appeal for a ban on the testing of nuclear weapons. By late 1957 he and Ava Helen had circulated letters that garnered more than nine thousand signatures from scientists in forty-nine countries on a petition that they presented to United Nations (UN) Secretary-General Dag Hammarskjöld at the UN in January 1958, supplemented by an additional two thousand signatures received shortly afterward. In the same year Pauling’s book No More War! appeared. At this time President Dwight D. Eisenhower and Secretary of State John Foster Dulles tended to support a test ban, while the Department of Defense and the AEC opposed it. At the end of 1958 the United States, United Kingdom, and Soviet Union agreed to a moratorium on nuclear weapons testing, but the Soviet leader Nikita Khrushchev announced the end of the moratorium after the French government tested their first atomic bomb in the Sahara Desert in 1960. By this time Pauling had been subpoenaed by the U.S. Senate Internal Security Subcommittee to explain possible Communist involvement in the nuclear-test ban movement and refused, under threat of being held in contempt, to reveal the names of those who helped circulate the UN petition. The Cuban missile crisis of 1962 moved the United States and Soviet Union to a focused effort on achieving in August 1963 a Limited Test Ban Treaty, which allowed only underground nuclear testing.

In December 1963 Pauling received the deferred 1962 Nobel Peace Prize. The reaction from his colleagues and the public was a divided one because many people had come to identify Pauling with radical or suspect political actions considered unfitting for a responsible scientist. Caltech’s president Lee DuBridge had asked Pauling in 1958 to resign as chairman of the chemistry and chemical engineering division on the grounds that Pauling’s attention was insufficiently focused on his laboratory and his department. When DuBridge made a public statement acknowledging the difference of opinion among Pauling’s colleagues about Pauling’s campaign against nuclear war, Pauling announced in October 1963 that he was leaving the institution with which he had been associated since 1922. After the Journal of the American Chemical Society mentioned the peace prize only in a single paragraph in the back pages of an issue, Pauling resigned from the American Chemical Society, whose presidency he had held in 1949.

Vitamin C and Molecular Medicine Pauling’s next years were spent in several institutions: 1963 to 1967 as a research professor at the Center for the Study of Democratic Institutions in Santa Barbara; 1967 to 1969 as professor of chemistry at the University of California at San Diego; 1969 to 1972 as professor of chemistry at Stanford University; and 1973 to 1992 as chairman of the board of trustees for the Laboratory of Orthomolecular Medicine, which he founded and which in 1974 became the Linus Pauling Institute of Science and Medicine in Palo Alto. Two new research interests emerged in the 1960s from some of his earlier work: the use of the hemoglobin protein molecule as an evolutionary clock and the application of vitamin therapy in molecular medicine.

Pauling proposed investigation of the idea of an evolutionary clock to Emile Zuckerkandl, who arrived as a postdoctoral fellow at Caltech in 1959. The project began as one to track the evolution, or mutations, of the molecule hemoglobin by comparing its size and structure in different animals. A study of horse hemoglobin, for example, showed that it differs from human hemoglobin by approximately eighteen amino-acid substitutions in each of its four chains. When this information was compared with paleontologists’ estimates of the divergence of horse and human lines, Pauling and Zuckerkandl arrived at a value of one evolutionary mutation every 14.5 million years in hemoglobin. They found that there was a closer relationship between the hemoglobin of humans and apes than between humans and orangutans, and they estimated that human and apes diverged more than 11 million years ago after their hemoglobin had stabilized. Pauling and Zuckerkandl’s work was pathbreaking in founding a new research specialty, with DNA soon replacing hemoglobin in the role of evolutionary clock. Zuckerkandl served as director of the Linus Pauling Institute from 1980 to 1991.

Pauling continued to think about sickle-cell anemia as a molecular disease and to consider how abnormal hemoglobin might have evolved as a mutagenic mistake that turned out to be helpful in preventing malaria. Pauling’s long bout with Bright’s disease, which is a disease linked to protein metabolism, likely contributed to his preoccupation with how diseases are caused and cured by molecules. In 1962 it occurred to Pauling that the human need for vitamins might be the result of molecular diseases contracted millions of years earlier. Not surprisingly he found attractive the hypothesis of the biochemist Irwin Stone that vitamin C in large doses is effective in treating viral diseases, heart disease, and cancer, and that humans’ inability to synthesize their own vitamin C is an evolutionary condition shared with other primates and only a few other mammals. Pauling also was intrigued with psychiatrists’ use of niacin in the treatment of schizophrenia as another instance of vitamin therapy, and he enlisted Arthur Robinson, who had completed a PhD with the chemist Martin Kamen at the University of California at San Diego, to head studies of mental diseases and therapies at Pauling’s institute.

In 1970 Pauling published a paper in PNAS on evolution and the need for ascorbic acid. The same year he published the best seller Vitamin C and the Common Cold, in which he surveyed the results of scientific trials on the preventive and therapeutic effects of doses of vitamin C ranging from 0.25 to 4.0 grams per day. In 1971 Dr. Ewan Cameron informed Pauling of his work near Glasgow in treating cancer patients with large doses daily of 10 grams of vitamin C. PNAS rejected a paper they coauthored, presaging the controversies that would follow in the next decade with members of the Mayo Clinic and the broader medical community over the merits of vitamins in the treatment of cancer. Pauling’s personal commitment to vitamin C became only more pronounced with the diagnosis in 1976 of Ava Helen Pauling’s stomach cancer, which led to her death in December 1981 after five years of good health following surgery and vitamin C therapy. In 1991, at the age of ninety, Pauling was diagnosed with rectal and prostate cancer, which was treated with surgeries and megadoses of vitamin C. He died at his ranch in Big Sur in August 1994.

Before his death, Pauling had the pleasure of seeing a change in attitude toward vitamin C therapies. In the fall of 1990 the National Cancer Institute (NCI) sponsored an international conference on “Ascorbic Acid: Biological Functions in Relation to Cancer,” to which he was invited as a speaker. In early 1992 the New York Academy of Sciences held a meeting that emphasized, like the NCI conference, the importance of vitamin C in enzymatic and nonenzymatic reactions, its effect in delaying tumor growth and prolonging survival times, and its action as an antioxidant that quenches free radicals implicated in the onset of cancer. After his death, the Linus Pauling Institute moved in 1996 to Oregon State University, where Pauling and Ava Helen had graduated. The institute continues to focus on the role of vitamins and essential minerals and plant chemicals in human health and disease.

Although Pauling’s public crusades in politics and medicine discredited him in some professional and public circles in the 1970s and early 1980s, the rancor had abated by the time of his death. On his eighty-fifth birthday, in 1986, Caltech declared an academic holiday and hosted a banquet where Pauling received praise as the greatest chemist of the twentieth century, a man deserving of a third Nobel Prize for his work on sickle-cell hemoglobin, and the true father of molecular biology. Pauling’s scientific work ranged broadly across physics, chemistry, biology, and medicine. His textbook General Chemistry, first published in 1947, defined a new chemistry just as The Chemical Bond had done in 1939. The 1947 textbook and its later editions emphasized both the dissimilarity and the similarity of chemistry and physics, and it taught chemistry on a firm theoretical foundation of electrons, atoms, and molecules with dimensions and images captured by three-dimensional models and by data from both physical instruments and chemical reactions. The high school chemistry curriculum in the United States in the 1960s was based in Pauling’s chemical bond approach, and Corey-Pauling Space Filling Models with Improved Koltun Connectors became as common in chemistry classrooms as the periodic table of the elements.

Pauling’s role as brilliant scientist and charismatic personality was not unlike Einstein’s in the twentieth century. Pauling was a legendary speaker and performer in lectures and public appearances, as well as a media star. Like Einstein, Pauling took delight in crossing boundaries and frontiers, and in confounding and even scandalizing his peers and colleagues. Neither Einstein nor Pauling lived tranquil lives, but they chose to become and remain public figures. Pauling was one of the great revolutionary scientists of the twentieth century, and few chemists doubt his place as the greatest of twentieth-century chemists.

BIBLIOGRAPHY

For a listing of all of Pauling’s publications, manuscripts, correspondence, and other materials, with commentary and illustrations, see The Pauling Catalogue: Ava Helen and Linus Pauling Papers at Oregon State University. 6 vols. Edited by Chris Petersen and Cliff Mead. Corvallis: Valley Library Special Collections, Corvallis, Oregon State University Libraries, 2006. The most detailed and comprehensive source for references to Pauling’s published and unpublished papers, details of his life, honors and degrees that he received, and essays and articles on his life and work with accompanying photographs, illustrations, and documents is the Web site at Oregon State University for the Ava Helen and Linus Pauling Papers in Special Collections at the Valley Library: http://osulibrary.oregonstate.edu/specialcollections/.

WORKS BY PAULING

With Samuel Goudsmit. The Structure of Line Spectra. New York: McGraw-Hill, 1930.

“The Nature of the Chemical Bond.” Parts I and II. Journal of the American Chemical Society 53 (1931): 1367–1400, 3225–3237.

“The Nature of the Chemical Bond.” Parts III and IV. Journal of the American Chemical Society 54 (1932): 988–1003, 3570–3582.

With George W. Wheland. “The Nature of the Chemical Bond.”Part V. Journal of Chemical Physics 1 (1933a): 362–374.

With Jack Albert Sherman. “The Nature of the Chemical Bond.” Parts VI and VII. Journal of Chemical Physics 1 (1933b): 606–617, 679–686.

With E. Bright Wilson. Introduction to Quantum Mechanics, with Applications to Chemistry. New York: McGraw-Hill, 1935.

The Nature of the Chemical Bond and the Structure of Molecules and Crystals: An Introduction to Modern Structural Chemistry.Ithaca, NY: Cornell University Press; London: Oxford University Press, 1939.

General Chemistry: An Introduction to Descriptive Chemistry and Modern Chemical Theory. San Francisco: W.H. Freeman, 1947.

With Robert B. Corey and Herman R. Branson. “The Structure of Proteins: Two Hydrogen-Bonded Helical Configurations of the Polypeptide Chain.” Proceedings of the National Academy of Sciences of the United States of America 37 (1951): 205–210.

With Robert B. Corey. “A Proposed Structure for the Nucleic Acids.” Proceedings of the National Academy of Sciences of the United States of America 39 (1953): 84–97.

No More War! New York: Dodd, Mead, 1958.

Vitamin C and the Common Cold. San Francisco: W.H. Freeman,

1970.

How to Live Longer and Feel Better. New York: W.H. Freeman, 1986. A reprint in paperback, with an introduction by Melinda Gormley, was published by Oregon State University Press in 2006.

Linus Pauling on Peace: A Scientist Speaks Out on Humanism and World Survival; Writings and Talks by Linus Pauling. Selected and edited by Barbara Marinacci and Ramesh Krishnamurthy. Los Altos, CA: Rising Star, 1998.

Linus Pauling: Selected Scientific Papers. 2 vols. Edited by Barclay Kamb et al. River Edge, NJ: World Scientific, 2001.

OTHER SOURCES

Dunitz, Jack D. “Linus Carl Pauling: February 28, 1901–August 19, 1994.” Biographical Memoirs of the National Academy of Sciences 71 (1997): 220–261. Available from http://www.nap.edu/readingroom/books/biomems/lpauling.html.

Francoeur, Eric. “Molecular Models and the Articulation of Structural Constraints in Chemistry.” In Communicating Chemistry: Textbooks and Their Audiences, 1789–1939, edited by Anders Lundgren and Bernadette Bensaude-Vincent. Canton, MA: Science History Publications, 2000.

Gavroglu, Kostas, and Ana I. Simões. “The Americans, the Germans, and the Beginnings of Quantum Chemistry.” Historical Studies in the Physical and Biological Sciences 25 (1994): 47–110.

Goertzel, Ted, and Ben Goertzel. Linus Pauling: A Life in Science and Politics. New York: Basic, 1995.

Hager, Thomas. Force of Nature: The Life of Linus Pauling. New York: Simon and Schuster, 1995.

Jolly, J. Christopher. “Linus Pauling and the Scientific Debate over Fallout Hazards.” Endeavour 26 (2002): 149–153.

Krishnamurthy, Ramesh, et al., eds. The Pauling Symposium: A Discourse on the Art of Biography. Corvallis: Oregon State University Libraries, 1996.

Mason, Stephen F. “The Science and Humanism of Linus Pauling (1901–1994).” Chemical Society Reviews 26 (1997): 29–39.

Nye, Mary Jo. “What Price Politics? Scientists and Political Controversy.” Endeavour 23 (1999): 148–154.

———. “Physical and Biological Modes of Thought in the Chemistry of Linus Pauling.” Studies in the History and Philosophy of Modern Physics 31B (2000): 475–492.

Richards, Evelleen. Vitamin C and Cancer: Medicine or Politics? New York: St. Martin’s Press, 1991.

Mary Jo Nye

Pauling, Linus Carl

(b. 28 February 1901 in Portland, Oregon; d. 19 August 1994 in Big Sur, California), renowned chemist and peace activist and the only person to receive two unshared Nobel Prizes.

Pauling was born and raised in Oregon. His father, Herman Henry William Pauling, was a modestly successful, self-taught druggist; his mother, Isabelle (”Belle”) Darling, was the descendent of a pioneer family. Pauling’s childhood was marked by tragedy, emotional isolation, and precocious independence. His father died when he was nine, leaving the small family, including Pauling’s mother and two younger sisters, alone and with limited means. Belle Pauling, devastated by the death of her husband and with her health crippled by pernicious anemia, used most of the family’s savings for a down payment on a boardinghouse on the edge of town. Driven by an anxious, often-bedridden mother, all three children worked at early ages to keep the house going.

After his father’s death, Pauling withdrew into books and hobbies. An interest in insects and minerals was followed, at age thirteen, by a fascination with chemistry spurred by a friend’s demonstration of simple home experiments using a toy chemistry set. Pauling gathered his father’s old pharmacy books, wheedled glassware from a drugstore salesman, smuggled chemicals and equipment home from an abandoned smelter, and created a homemade “laboratory” in a corner of the boardinghouse’s basement. Here he sought solace in learning the rules of chemistry and spent hours in free-form experimentation, much of it focused on the creation of substances capable of burning or exploding.

In high school a sympathetic chemistry teacher provided Pauling with special tutoring. This, combined with the attention of educated neighbors, helped the young man set his sights on college. By the time he was a high school senior, Pauling was self-confident enough to defy both his school principal, who refused to let him graduate early, and his mother, who wanted him to give up college in favor of a job in a local machine shop. At age sixteen he dropped out of high school and enrolled at Oregon Agricultural College (now Oregon State University), where he intended to pursue a degree in chemical engineering.

Away from home, Pauling blossomed. He quickly demonstrated that he knew more about chemistry than many of his professors. While still an undergraduate, he jumped at the chance to teach chemistry courses in the understaffed department, and he reaped two side benefits: greater access to current chemical journals, which he read avidly, learning the latest theories; and close proximity to dozens of young female students. One of the latter was an extremely bright and flirtatious Oregon girl named Ava Helen Miller. They were soon in love and married on 17 June 1923, a year after he received his B.S. degree from Oregon and after his first year in graduate school at the California Institute of Technology (Caltech). Miller remained a strong influence throughout his life.

Pauling developed an interest in the questions of how and why atoms bond together to make molecules, and Caltech, then a little-known, fledgling research institute, was a perfect place to study. He was one of the school’s first chemistry graduate students, beneficiary of a program devised by the renowned and innovative chemical educator A. A. Noyes. Pauling’s graduate work focused on a new and little-used analytical technique called X-ray crystallography, a complex and painstaking procedure in which beams of X rays were shot at crystals, the resulting scatter patterns visualized on photographs, and the patterns analyzed mathematically. If done correctly, the patterns indicated the positions of individual atoms in the crystal. Using this technique, researchers for the first time were able to map the distances and angles between individual atoms. The only problem was that the technique could only be used on very simple crystals. More complex substances yielded patterns too difficult to analyze. After a shaky start in the laboratory—Pauling’s talents were always more theoretical than experimental—he mastered the technique and earned his Ph.D. in 1925. At Noyes’s urging, he then spent fifteen months in Europe on a Guggenheim fellowship.

But knowing how atoms were arranged in molecules, something he could determine at least in simple cases with X-ray crystallography, was only half the story. Pauling also wanted to know the nature of the chemical bond that caused atoms to join together in certain ways and not others. To find the answer, he focused his studies on physics. His timing was propitious. In Europe a new and powerful advance in physics, quantum mechanics, was being born in the late 1920s, and Pauling was lucky enough to learn it from its creators, including Arnold Sommerfeld, Werner Heisenberg, Wolfgang Pauli, Niels Bohr, and Erwin Schrödinger.

After returning to Caltech as a young faculty member in 1927, Pauling embarked upon an extraordinary professional career, beginning the task of rebuilding chemistry on the foundation of quantum mechanics. His approach involved an intuitive mix of bold theory and empirical research, memorable lectures, persuasive papers, and best-selling textbooks. He was a communicator as well as an innovator. The new physics was mathematically challenging for all but a handful of chemists in the late 1920s, but Pauling knew how to simplify the math and describe results at a level chemists could quickly grasp.

He was also successful at discovering the structures of complex substances. Pauling used X-ray crystallography to gauge the distances and angles between atoms in simple crystals, then used the results as guides to what was or was not possible regarding more complex structures. By whittling down the possibilities, he was able to make highly educated guesses at structures for more complex substances. He would then toss the remaining theoretical structures in the wind of quantum mechanics, blowing away those that were not in accordance with the principles of the new physics. Once he eliminated as much chaff as possible, Pauling tested the best remaining structures by seeing how they looked, creating three-dimensional molecular models out of paper, wire, and wood. The single most plausible remaining structure he would test once again by predicting the ways it would behave, including its melting and boiling points and its X-ray patterns. If the model matched the qualities of the real molecule, he would publish his findings.

It was a brilliant approach and it worked. Pauling believed two things strongly: that rules of chemistry and physics determined how molecules were built, and that the structure of molecules explained their activity. He played both ends. Knowing the rules, he could eliminate and illuminate possible structures; knowing the structures, he could amend and refine the rules. His memory was prodigious and his approach independent. He appeared cognizant of few boundaries, dancing gracefully between physics and chemistry, laboratory results and theory. In a dazzling series of papers throughout the 1930s, Pauling made important advances in determining the structures of complex minerals as well as describing the chemical bond in quantum mechanical terms. This work was capped in 1939 with the publication of The Nature of the Chemical Bond, one of the most-cited texts in science history.

By then, at age thirty-eight, Pauling was a full professor; head of the chemistry division at Caltech; the youngest person ever elected to membership in the National Academy of Sciences; and father of three sons and a daughter.

In the mid-1930s Pauling took his research in a new direction. The Rockefeller Foundation at that time was directing significant funding toward defining the molecules essential to life. Lured by Rockefeller support, Pauling turned his attention to the structure of biomolecules, especially proteins such as hemoglobin and antibodies. These were gigantic structural problems, molecule orders of magnitude more complex than any Pauling had worked with before. But again his hard work, deep understanding of simpler chemical structures, and model-building approach brought him success. Over the next fifteen years he made important discoveries about hemoglobin, including tracking the cause of sickle-cell anemia to changes of a few atoms among many thousands. Pauling also studied antibodies, producing the most sophisticated work at the time regarding the structural relationship between antibody and antigen. In addition, he investigated enzymes and other proteins. The capstone of this work was the publication in May 1951 of seven papers detailing the structures of a number of proteins at the level of individual atoms.

Pauling developed the powerful idea that biological specificity (the precise matching of antibody and antigen, for example, or the ability of an enzyme to react with only one substrate) was due to complementarity, in which the shape of one molecule precisely fits another like a key in a lock. This structural insight was critical to the development of molecular biology. For his achievements in structural chemistry Pauling was awarded the 1954 Nobel Prize in Chemistry.

By then, however, Pauling’s maverick temperament had made him well known for something other than science. At the urging of his wife, he began focusing on stopping the development and spread of atomic weapons. Many scientists shared Pauling’s antinuclear sentiments, but few were as outspoken or perseverant. A proponent of world government and democratic socialism, Pauling had no qualms about attacking U.S. government policies he deemed wrong. Federal authorities responded by putting him under FBI surveillance, canceling research grants, refusing him a passport, and stripping him of his security clearance. Senator Joseph McCarthy accused him of being a communist, and the press smeared Pauling; still, he carried on.

By the late 1950s Pauling was a world leader in the peace movement. In 1957 and 1958 he and his wife gathered the signatures of some 11,000 scientists on a global petition to end nuclear weapons testing and presented it to the United Nations. He was finally rewarded: the day after the first nuclear test ban treaty went into effect on 10 October 1963, Pauling learned that he had won the Nobel Peace Prize. Instead of warm public support following the award, however, Pauling encountered criticism. The New York Herald-Tribune dubbed him a “placarding peacenik,” and Life magazine called the prize “a weird insult from Norway.” Many observers felt that President John F. Kennedy should have won the award instead.

During his years of political activism, Pauling’s science foundered. Following a failed attempt to find a structure for deoxyribonucleic acid (DNA), he moved his research increasingly toward the study of what he termed “molecular medicine.” Pauling believed that the body could be viewed as an array of chemical reactions. Optimal health, in his view, could thus be achieved if the reaction conditions were right and the proper molecules present in the proper amounts. He spent years trying to find a molecular basis for mental disease, ways to counter inborn metabolic conditions, and a theory of anesthesia. But here Pauling’s theories outstripped the technology of the time: the complexity and subtlety of biochemical systems in living organisms required more sophisticated analytical tools than had yet been invented. Each of his lines of investigation, while promising, refused to yield definitive results. His only significant scientific success during this period was a theory, developed with Emile Zuckerkandl, outlining how tracking the differences in similar biomolecules (such as hemoglobins) between various species could be used as a clock to time evolutionary divergence. The “molecular clock” idea has since proven important for evolutionary biology.

His Caltech colleagues in the late 1950s began grumbling about Pauling’s fruitless pursuit of medical findings instead of basic chemistry. The president of Caltech and a number of trustees were concerned about his reputation as a left-wing agitator. As a result, in the late 1950s Pauling lost the chairmanship of the Caltech chemistry division, along with a good deal of his laboratory space. It was an insult he never forgot. One week after winning the Nobel Peace Prize, Pauling announced that he was leaving Caltech.

He spent the next decade as an academic nomad, working at various think tanks and universities, never finding a suitable intellectual home. Pauling spent much of the 1960s working on unifying ideas, including a system of ethics based upon science, as well as a book on the molecular basis of civilization, but nothing was published.

In the late 1960s Pauling became interested in the health effects of a single vitamin, ascorbic acid or vitamin C, which some evidence indicated had beneficial effects on everything from the common cold to cancer, but his controversial and widely publicized claims were strongly criticized by the medical community. There is no doubt that his work helped change the nutritional habits of millions of people, and a growing body of evidence in later years underscored the importance of high doses of vitamins, including C, in promoting health. In 1973 Pauling cofounded a California research institute devoted to the study of the health effects of vitamin and other nutrients. There he conducted research until his death from cancer at age ninety-three. He had long outlived Ava Helen, who died thirteen years earlier, on 7 December 1981.

Pauling had a substantial effect on the history of science. Modern chemistry owes a great deal to his ability to explain chemistry in quantum mechanical terms, and to successfully apply his strongly structural approach to the form and function of complex organic and inorganic molecules. Pauling’s insights about the importance of complementarity between giant molecules as a basis for biological specificity became an important approach for the new field of molecular biology—a field in which Pauling can be rightly considered a founding father.

Using his scientific fame as a springboard for political activism, Pauling became an important figure in the worldwide peace movement of the 1950s. His perseverance in the face of persecution was admirable; his rallying of scientific opinion against atmospheric nuclear testing was critical in achieving public sentiment in favor of a test ban. But perhaps history will judge Pauling most kindly for his character rather than his deeds. Especially in the current era of bland, poll-based, middle-of-the-road politics, Pauling’s maverick outspokenness and willingness to risk his career for what he thought to be right appears increasingly admirable.

Pauling’s personal and scientific papers are available in the Oregon State University Special Collections in Corvallis, Oregon. Additional Pauling-related material is available in the archives of the California Institute of Technology. Several overviews of his life are available, including Thomas Hager, Force of Nature: The Life of Linus Pauling (1995) and Linus Pauling and the Chemistry of Life (1998); and Ted and Ben Goertzel, Linus Pauling: A Life in Science and Politics (1995). Also useful is Barbara Marinacci, ed., Linus Pauling in His Own Words (1995). Obituaries are in the Los Angeles Times (20 Aug. 1994), New York Times (21 Aug. 1994), and Chicago Tribune (28 Aug. 1994).

Thomas Hager

Linus Carl Pauling

The American chemist, Linus Carl Pauling (1901-1994), was twice the recipient of a Nobel Prize. He clarified much that was obscure in the determination of the exact tri-dimensional shapes of molecules, revealed the nature of the chemical bond, helped to create the field of molecular biology, proposed the concept and coined the term "molecular disease;" founded the science of ortho-molecular medicine, and was an activist for peace.

Linus Carl Pauling was born in Portland, Oregon, on February 28, 1901. He was the first of three children born to Herman Henry William Pauling and Lucy Isabelle "Belle" (Darling) Pauling. His father was a druggist who struggled to make a living for his family. With his business failing, Herman Pauling moved the family to Oswego, seven miles south of Portland, in 1903. But, he was no more successful in Oswego and moved the family to Salem in 1904, to Condon (in northern Oregon) in 1905, and back to Portland in 1909. In 1910 his father died of a perforated ulcer, leaving his mother to care for the three young Pauling children.

As a child, Pauling read continuously and, at one point, his father wrote to the local newspaper asking for readers to suggest additional books that would keep his young son occupied. His interest in science was apparently stimulated by his friend, Lloyd Jeffress, during his grammar school years at Sunnyside Grammar School. Jeffress kept a small chemistry laboratory in a corner of his bedroom where he performed simple experiments. Pauling was intrigued by these experiments and decided to become a chemical engineer.

During his high school years, Pauling continued to pursue his interest in chemistry. He was able to obtain much of the equipment and materials he needed for his experiments from the abandoned Oregon Iron and Steel Company in Oswego. His grandfather was a night watchman at a nearby plant and Pauling was able to "borrow" the items he needed for his own chemical studies. Pauling would have graduated from Portland's Washington High School in 1917 except for an unexpected turn of events. He had failed to take the necessary courses in American History required for graduation and, therefore, did not receive his diploma. The school corrected this error 45 years later when it awarded Pauling his high school diploma—after he had been awarded two Nobel Prizes.

In the fall of 1917 Pauling entered Oregon Agricultural College (OAC), now Oregon State University, in Corvallis. He was eager to pursue his study of chemical-engineering and signed up for a full load of classes. But finances soon presented a serious problem. His mother was unable to pay family bills at home and, as a result, Pauling regularly worked 40 or more hours a week in addition to studying and attending classes. By the end of his sophomore year, he could not afford to stay in school and decided to take a year off and help his mother by working in Portland. At the last minute, OAC offered him a job teaching quantitative analysis, a course he had completed as a student just a few months earlier. The $100-a-month job allowed him to return to OAC and continue his education.

During his junior and senior years, Pauling learned about the work of Gilbert Newton Lewis and Irving Langmuir on the electronic structure of atoms and the way atoms combine with each other to form molecules. He became interested in how the physical and chemical properties of substances are related to the structure of the atoms and molecules of which they are composed and decided to make this topic the focus of his own research.

During his senior year, he met Ava Helen Miller while teaching chemistry in a home-economics class. They were married June 17, 1923, and later had four children: Linus Jr., born in 1925; Peter Jeffress, born in 1931; Linda Helen, born in 1932; and Edward Crellin, born in 1937.

Pauling received his bachelor's degree from OAC on June 5, 1922 and began attending the California Institute of Technology (Cal Tech) in Pasadena the following fall. He received his doctorate summa cum laude in chemistry (with minors in physics and mathematics) on June 12, 1925. During his graduate studies, he was assigned to work with Roscoe Gilley Dickinson on the X-ray analysis of crystal structures. His first paper, published in the Journal of the American Chemical Society (JACS) in 1923, was a direct result of this work. Pauling's entire scientific life is connected with Cal Tech and he would publish six more papers on the structure of other minerals before graduation.

After graduation, Pauling decided to travel to Europe and study in the new field of quantum mechanics with Arnold Sommerfeld in Munich, Niels Bohr in Copenhagen, and Erwin Schrodinger in Zurich. The science of quantum mechanics was less than a decade old and based on the revolutionary concept that particles can sometimes have wave-like properties, and waves can sometimes best be described as if they consisted of mass-less particles. He had been introduced to quantum mechanics while at OAC and was eager to see how this new way of looking at matter and energy could be applied to his own area of interest. After two years in Europe, he and Ava left Zurich and returned to Cal Tech.

Pauling was appointed to Cal Tech's faculty of theoretical chemistry in the fall of 1927 as an assistant professor and would stay on there until his leave as a full professor of chemistry in 1963. In addition, from 1937 to 1958, he headed the Gates and Crellin Chemical Laboratories.

The central theme of Pauling's work was always the understanding of the properties of chemical substances in relation to their structure. He began by determining the crystal structure of various inorganic compounds and complexes with a view to deriving from these the principles governing the structure of molecules. He went on to the prediction of the chemical and physical properties of atoms and ions based upon theoretical considerations. In 1928 Pauling introduced rules relating to the stability of complex ionic crystals which greatly facilitated structural studies.

Pauling spent the summer of 1930 traveling around Europe visiting the laboratories of Laurence Bragg in Manchester, Herman Ludwigshafen and Sommerfeld in Munich. In Ludwigshafen, Pauling learned about the use of electron diffraction techniques to analyze crystalline materials. Over the next 25 years, Pauling and his colleagues would use this technique to determine the molecular structure of more than 225 substances.

Using what he had learned over the summer, Pauling and R.B. Corey began studying the structure of amino acids and small peptides. They postulated that polypeptide chains, especially those derived from fibrous proteins, form spirals of a particular configuration—this was the alpha helix. On April 6, 1931, Pauling published the first major paper on this topic ("The Nature of the Chemical Bond") and was awarded the American Chemical Society's Langmuir Prize for "the most noteworthy work in pure science done by a man 30 years of age or less."

This was a bold proposal for the newly appointed full professor to make. But it has been repeatedly confirmed since, and is now known to apply also to significant portions of the polypeptide chains in the so-called "globular proteins." Pauling would write six more papers on the same topic, continually refining his work.

In some ways, the 1930s mark the pinnacle of Pauling's career as a chemist. During that decade he was able to apply the principles of quantum mechanics to solve a number of important problems in chemical theory.

In 1939 Pauling published his book The Nature of the Chemical Bond and the Structure of Molecules and Crystals. This book has been considered by many as one of the most important works in the history of chemistry. The ideas presented in the book and related papers are the primary basis upon which Pauling was awarded the Nobel Prize for Chemistry in 1954.

In the mid-1930s Pauling was looking for new fields to explore and soon found his interest turning to the structure of biological molecules. This was a surprising choice for Pauling, because earlier in his career he had mentioned that he wasn't interested in studying biological molecules. The interest of the newly-formed department of biology at Cal Tech in hemoglobin was derived from the discovery by Pauling and C.D. Coryell in 1936 of a change in the magnetic properties of hemoglobin upon oxygenation. These studies, although they dealt mainly with heme structure, led to an interest in the globin portion of the molecule. This finally culminated in the 1949 proposal that humans may manufacture more than one kind of adult hemoglobin. Sickle-cell anemia was shown to be due to the presence of a type of hemoglobin which tends to aggregate and crystallize under conditions of reduced oxygen, with distortion and malfunctioning of the red blood cell. This was the first documented instance of a "molecular" disorder, a discovery of major import to medicine, biochemistry, genetics, and anthropology.

The 1940s were a decade of significant change in Pauling's life. He had never been especially political and, in fact, had only voted in one presidential election prior to World War II. But in this decade he quickly began to immerse himself in political issues. One important factor in this change was the influence of his wife, who had long been active in a number of social and political causes. Another factor was probably the war itself. As a result of his own wartime research on explosives as a principal investigator for the Office of Scientific Research and the National Defense Research Commission, Pauling became more concerned about the potential destructiveness of future wars. As a result, he decided while on a 1947 trip to Europe that he would raise the issue of world peace in every speech he made in the future, no matter what the topic.

From that point on, Pauling's interests turned from scientific to political topics. He devoted more time to speaking out on political issues, and the majority of his published papers dealt with political, rather than scientific, topics. In 1957, with the help of his wife and many others, he organized a petition calling for an end to nuclear bomb testing. In January of the following year, he presented this petition at the United Nations with over 11,000 signatures from scientists all over the world. In 1958 he published his views on the military threat facing the world in his book No More War!

His views annoyed many in the scientific and political communities and he was often punished for these views. In 1952 the U.S. State Department denied him a passport to attend an important scientific convention in England because his anti-communist statements were not "strong enough." Only after his fourth try did he succeed in receiving a "limited passport." In 1960 he was called before the Internal Security Committee of the U.S. Senate to explain his antiwar activities. But neither popular nor professional disapproval could keep Pauling from protesting, writing, speaking, and organizing conferences against the world's continuing militarism. In recognition of these efforts, Pauling was awarded the 1963 Nobel Prize for Peace.

In 1966 Pauling again found a new field to explore: the possible therapeutic effects of vitamin C. Pauling was introduced to the potential value of vitamin C in preventing colds by biochemist Irwin Stone. He soon became intensely interested in the topic and summarized his views in the 1970 book Vitamin C and The Common Cold.

In 1974 Pauling testified before the U.S. Senate Subcommittee on Health on food supplement legislation. He advocated controls over vitamins but did not want to classify them as drugs. In 1986 he published How To Live Longer and Feel Better, and in 1990, along with Daisaku Ikeda Seimei, he published In Quest of the Century of Life—Science and Peace and Health.

Pauling's views on vitamin C have received relatively modest support in the scientific community. Many colleagues tend to feel that the evidence supporting the therapeutic effects of vitamin C is weak or nonexistent, though research on the topic continues. Other scientists are more convinced by Pauling's argument. He is regarded by some as the founder of the science of ortho-molecular medicine, a field based on the concept that substances normally present in the body (such as vitamin C) can be used to prevent disease and illness.

Pauling's long association with Cal Tech ended in 1963, at least partly because of his active work in the peace movement. He "retired" to become a research professor in the physical and biological sciences at the Center for the Study of Democratic Institutions in Santa Barbara, California. He went on to teach chemistry at the University of California in San Diego and Stanford University in Palo Alto. In 1972 he founded, along with Arthur B. Robinson and Keene Dimick, the Institute of Orthomolecular Medicine as a non-profit California organization to engage in scientific research. Later, it was re-named the Linus Pauling Institute of Science and Medicine.

Pauling received many awards during his successful career. He was a member of the National Academy of Sciences and of the Royal Society, from which he received the Davy Medal in 1947; the American College of Physicians presented him with its Phillips Memorial Award in 1956; and in the same year he received the Avogadro Medal from the Italian Academy of Sciences.

On August 19, 1994 Pauling died of cancer at his ranch outside Big Sur, California. After his death, research continued on every aspect of his earlier discoveries, especially his theory on vitamin C and its effects on disease and the human body. His career exemplified the highly productive results that clear theory along with daring experimental approaches and a courageous imagination can bring.

Further Reading

Short biographies of Pauling are in Eduard Farber, Nobel Prize Winners in Chemistry, 1901-1961 (rev. ed. 1963), and Nobel Foundation, Chemistry: Including Presentation Speeches and Laureates's Biographies (1964). A personal reminiscence of Pauling and his scientific work is in James Dewey Watson, The Double Helix: A Personal Account of the Discovery of the Structure of DNA (1968). Pauling's efforts for peace and disarmament are recounted in detail in Mortimer Lipsky, Quest for Peace: The Story of the Nobel Award (1966).

Other biographies of Pauling appear in Anthony Serafini Linus Pauling: A Man and His Science (1989) and Ted George Goertzel Linus Pauling: A Life In Science and Politics (1995). Probably the best source for information on Pauling is maintained by the Oregon State University Library with its Ava Helen and Linus Pauling Papers, which were donated in 1986 by Pauling himself and are available on-line at www.orst.edu. □

PAULING, Linus Carl

(b. 28 February 1901 in Portland, Oregon; d. 19 August 1994 in Big Sur, California), chemist, physicist, and biologist who won the 1954 Nobel Prize in chemistry and a Nobel Peace Prize in 1962—the only person who has won two undivided Nobel Prizes; he revolutionized both inorganic chemistry and organic chemistry, identified how sickle-cell anemia works, and was an outspoken advocate for nuclear disarmament and appeasement of the Soviet Union.

Pauling was the first of three children born to a druggist, Herman W. Pauling, and a homemaker, Lucy Isabelle ("Belle") Darling Pauling, descendants of frontier settlers. Herman Pauling died in June 1910. Pauling attended Washington High School in Portland but left without graduating, already having enough high school credits for admission to Oregon Agricultural College (OAC), which he entered in September 1917. In 1919 his mother died. He met the greatest influence on his life and career, Ava Helen Miller, during his senior year at OAC. She was only a sophomore in 1922, when he left for graduate school at the California Institute of Technology (Cal Tech). They married on 17 June 1923.

Family life placed new demands on Pauling with the birth of Linus, Jr., in March 1925. After receiving his doctorate summa cum laude in 1925, Pauling received a Guggenheim Fellowship to study in Munich, Germany, where he worked on chemical bonding with top researchers. His numerous papers on the subject in the 1920s and 1930s opened new fields of research. However, his relationship with his wife became strained during the years he was in Germany (1925–1927) because she remained in California. It was a relief to both of them when he accepted an assistant professorship at Cal Tech in 1928, and they settled down to raise their three sons and one daughter. Pauling eventually became chairman of the division of chemistry and chemical engineering, a post he held from 1936 to 1958. In the mid-1930s his work began to shift from inorganic chemistry to biochemistry. In 1939 he published The Nature of the Chemical Bond (revised in 1967), which became the seminal, revolutionary work in the field.

It was during World War II that Pauling began to take a strong interest in politics. The physician who saved his life from nephritis was a Communist and suffered government reprisals, eventually losing his practice, and the government wanted to intern the Japanese-American gardener the Paulings employed. J. Robert Oppenheimer asked Pauling to join the Manhattan Project, which was charged with creating the first nuclear weapons; Pauling refused, but he became interested in nuclear weapons at this time. In the late 1940s his insights into sickle-cell anemia led to treatments for the disease while shedding new light on genetic diseases in general. In 1954 Pauling was awarded the Nobel Prize in chemistry for his work on chemical bonding, and there were those in the scientific community who thought he should receive the Nobel Prize in physiology or medicine for the application of his discoveries to sickle-cell anemia as well.

Meanwhile, matters at Cal Tech were not going well. During the 1930s and 1940s Pauling had joined with other atheists at the school to deny employment or promotions to any professor who had a spiritual life. In so doing, in the fierceness of his commitment, he crossed the line from bias to outright bigotry. Eventually he also worked to discriminate against anyone who was not politically left wing. Yet he did not agree with Cal Tech's late-1950s decision to add courses in the humanities, many of which were taught from a left-wing point of view, to the curriculum. He considered them a waste of time.

By the 1960s Pauling seemed exhausted, and he canceled some of his scientific projects. The only issue that seemed to galvanize him was the testing of nuclear weapons, and he became a leading advocate of nuclear disarmament, writing articles about the effects on people of radiation from nuclear tests. On 10 October 1962 he was awarded the Nobel Peace Prize for his work in communicating the dangers posed by radiation from testing nuclear weapons. People on both sides of the issue seemed to misunderstand why he merited the prize, with those on the left praising his political correctness and those on the right complaining that he was merely trying to appease the Soviets. In fact, his political views were controversial; it was his science that was important in that his work showing that radiation and residue from nuclear tests were harmful to humans and their environment helped lead to test ban treaties. A major test ban treaty was signed on the very day that Pauling received the Peace Prize; many observers were convinced of the relationship between the two events.

Pauling was heavily criticized for his radical politics in many magazines and newspapers around the world, although he received support from leftist publications. He advocated the unilateral disarmament of the United States and the United Kingdom, arguing that the Soviet Union would then disarm because it would no longer feel threatened. This point of view ignored the obvious aggression by the Soviet Union in Europe and China as well as fears in the United States and Western Europe that the Soviet Union posed a serious and continuing threat. By the mid-1960s Pauling had formed the habit of suing for libel any publication that suggested he might be a Communist or "fellow traveler" who favored the Soviet Union over his own country. (That a disarmed Western world would be easy pickings for a nuclear-armed Soviet Union was often pointed out by publications such as the National Review.) Nearly always, the publications he sued settled out of court.

On 17 July 1962 the conservative National Review suggested Pauling was a "collaborator," and Pauling threatened to sue. The editor of the National Review was William F. Buckley, Jr., who relished the prospect of a fight and refused to settle Pauling's claim. The resulting court battle damaged Pauling's reputation because the National Review showed that Pauling had broken American law by corresponding with Ho Chi Minh while the United States was at war with North Vietnam. The lawsuit resulted in a landmark ruling that changed how journalists were allowed to write about famous people. On 19 April 1964 Judge Samuel J. Silverman ruled that all public figures, not only politicians, had to prove actual "malice" to win a libel suit; "defamation" was insufficient. This ruling has allowed American journalists to write with almost unfettered freedom about anyone who is in the public eye—even lying—as long as "malice" cannot be proven. On 30 June 1964, tired and demoralized, Pauling resigned from Cal Tech because of the faculty's resentment concerning both his politics and his continuing habit of taking credit for work done by others. For the next few years he worked on a new edition of The Nature of the Chemical Bond.

Pauling served as professor of chemistry at the University of California, San Diego, from 1967 to 1969. He found working at San Diego congenial, but in 1969 Stanford University offered him more money, more spacious and up-to-date laboratories, and more research assistants as well as the opportunity to live at his beloved home in Big Sur. He accepted the Stanford position, and during the next five years tried to apply his knowledge of chemistry, physics, and genetics to unlock treatments for diseases. Somewhere in the intricacies of chemical bonding and the double helix, he believed, were answers not only for sickle-cell anemia but also for viral infections such as colds and for some cancers, especially those linked to viruses. He thought he had found an answer in vitamin C, which seemed to re-inforce the structure of DNA, thus having the potential to fend off mutations that seemed to be at the heart of cancer.

In 1970 the most widely influential of Pauling's books, Vitamin C and the Common Cold, was published. In it Pauling argued that taking vitamin C as a dietary supplement could protect people from colds and other viral diseases. Later he argued that megadoses of vitamin C could cure some kinds of cancer. A majority of specialists in viruses and cancer disagreed. For a lifetime of achievement in science, however, Pauling received the National Medal of Science from President Gerald Ford on 18 September 1975.

Pauling and the researcher Arthur Robinson founded the Pauling Institute in the 1970s to further pure research. Robinson was marvelous at raising money, but he aroused Pauling's deeply held prejudices when he publicly declared he was a capitalist and in his writings suggested that vitamin C taken in large quantities could be carcinogenic. Pauling was outraged at Robinson's political views and took it as a personal insult that Robinson's laboratory work should seem to disagree with his theories. He and his partner dissolved their relationship, and Pauling erased him from his life.

On 7 December 1981 Pauling's wife died of stomach cancer. Pauling continued writing scientific papers until his death from prostate cancer on 19 August 1994. He was cremated and his ashes were scattered.

Pauling's was an exceptionally productive life. Neither his mean-spiritedness, his tendency to take credit for other people's work, nor his politics detract from his greatness as a scientist. His work in several scientific fields is an example of how a true scientist applies his mind and skill to problems. Out of his dogged and brilliant work emerged new scientific disciplines as well as solutions to fundamental chemical, physical, and biological questions that laid the groundwork for expanding research and knowledge. He may have been his era's greatest chemist; he may be the greatest of all biochemists; and his work on sickle-cell anemia and on the effects of nutrition on diseases opened new avenues for understanding and treating illness.

The Ava Helen and Linus Pauling papers are housed in Special Collections, The Valley Library, Oregon State University, in Corvallis. Probably the most objective account of Pauling's life is Anthony Serafini's Linus Pauling: A Man and His Science (1989), which not only describes Pauling's strengths and weaknesses but offers good, clear explanations of his scientific work. An interesting, although short, account of Pauling's science is Francis Crick's "LP + C + 2NP Is Not Equal to DNA" in the New York Times Magazine (1 Jan. 1995): 18. An obituary is in the New York Times (21 Aug. 1994).

Kirk H. Beetz

Pauling, Linus

AMERICAN CHEMIST
1901–1994

Linus Carl Pauling was born in Portland, Oregon, on February 28, 1901, the first of three children of pharmacist Herman W. Pauling and Lucy Isabelle Pauling (née Darling). An internationally acclaimed scientist, educator, humanitarian, and political activist, the only person to have received two unshared Nobel Prizes (for chemistry in 1954; for peace in 1962), Pauling was once characterized by New Scientist as one of the twenty greatest scientists of all time, on a par with Isaac Newton, Charles Darwin, and Albert Einstein. His magnum opus, The Nature of the Chemical Bond (1939), was one of the most influential and frequently cited scientific books of the twentieth century. His advocacy of megadoses of vitamin C for the common cold, cancer, and AIDS is still controversial, and the work for which he is best known. His life and career were characterized by controversy, and almost everything about him was larger than life.

Pauling majored in chemical engineering at Oregon Agricultural College (now Oregon State University), where he developed the belief that would guide his lifetime of research: Atomic arrangements must be responsible for the chemical and physical properties of material substances. He received his B.S. degree in 1922 and entered the California Institute of Technology (Caltech) at Pasadena, where he worked with Roscoe G. Dickinson and adopted the relatively new technique of x-ray crystallography to explore the structure of crystals. In 1925 Pauling received his Ph.D. and was awarded a Guggenheim fellowship to pursue postgraduate research in Europe with the seminal atomic theorists Arnold Sommerfeld, Niels Bohr, and Erwin Schrödinger. The first to realize the ramifications of the new quantum mechanics within chemistry, he used this body of ideas to explain and predict the properties of atoms and ions, and thus to revolutionize chemistry. In 1927 Pauling returned to Pasadena to join the faculty of Caltech, where he stayed until 1963. There he used x-ray diffraction to measure the lengths and angles of atomic bonds in the three-dimensional structures of, first, inorganic crystals and, later, organic compounds.

One of the key concepts of Pauling's quantum theory of chemical bonding, introduced in 1931, was resonance: In many cases an ion or molecule could not be represented, conceptually or on paper, as one classical structure, but required what he called a "hybridization" of two or more of these structures. The single classical structure simply did not describe the chemical bond(s). In less than a decade he had transformed the earlier, somewhat simplistic theory of the chemical bond into a powerful, highly sophisticated theory and research tool. During the mid-1930s Pauling turned his attention to molecules present in living things. His interest in the binding of oxygen to hemoglobin (the protein molecule that carries oxygen via the bloodstream to cells throughout the body) provoked a more general interest in proteins, the nitrogen-containing organic compounds required in all of animal metabolism . In 1948, while in bed with influenza, Pauling occupied himself with making a paper model of linked amino acids, the basic building blocks of proteins. In this way he received the inspiration that led to his discovery of the α -helix —a crucial concept that helped James Watson and Francis Crick to determine the structure of DNA , one of the discoveries of the century. And this landmark discovery of Watson and Crick led, ultimately, to the Human Genome Project and the current revolution in genetic engineering.

After World War II Pauling studied sickle cell anemia, and theorized that it was the result of a genetically based defect in the patient's hemoglobin molecules. In 1949 he and Harvey Itano confirmed this theory; they had identified what they called a "molecular disease," one that could be defined by a molecular abnormality. In 1954 Pauling received the Nobel Prize in chemistry "for his research on the chemical bond and its application to the elucidation of the structure of complex substances."

Less well-known is the record of Pauling's evolution from ivory tower scientist to ardent and articulate advocate of nuclear disarmament and of the social responsibility of scientists. His eventual clashes with political and ideological adversaries, including the U.S. government, which denied him research grants and a passport, consumed much of his time and energy. His being chosen for the 1962 Nobel Peace Prize was criticized by many, and the American Chemical Society, which he had served as president in 1949, at around this time chose to slight him.

In 1963 Pauling left Caltech to become research professor at the Center for the Study of Democratic Institutions at Santa Barbara, California, at which time he began to divide his time between chemistry and world peace. In Santa Barbara he became greatly interested in what he called "ortho-molecular medicine"—a biochemical approach to human health that included the central idea that large amounts of some chemical compounds normally present in the body could be used to treat or prevent disease. In 1973, following professorships at the University of California, San Diego (1967–1969) and Stanford University (1969–1974), he founded the Institute of Orthomolecular Medicine (later named the Linus Pauling Institute of Science and Medicine), an organization of which he was director of research at the time of his death. He died of cancer at his Deer Flat Ranch near Big Sur, California, on August 19, 1994, at the age of ninety-three.

Pauling has been called one of the two greatest scientists of the twentieth century (the other being Einstein) and the greatest chemist since Antoine-Laurent Lavoisier, the eighteenth-century founder of modern chemistry. Pauling's multifaceted life and activities, scientific and personal, spanned almost the entire twentieth century.

see also Bohr, Niels; Einstein, Albert; Hemoglobin; Lavoisier, Antoine; Newton, Isaac; Proteins; SchrÖdinger, Erwin; Watson, James Dewey.

George B. Kauffman

Bibliography

Goertzel, Ted, and Goertzel, Ben (1995). Linus Pauling: A Life in Science and Politics. New York: Basic Books.

Hager, Thomas (1995). Force of Nature: The Life of Linus Pauling. New York: Simon & Schuster.

Hager, Tom (1998). Linus Pauling and the Chemistry of Life. New York: Oxford University Press.

Kauffman, George B., and Kauffman, Laurie M. (1996). "An Interview with Linus Pauling." Journal of Chemical Education 73:29–31.

Marinacci, Barbara, ed. (1995). Linus Pauling: In His Own Words: Selected Writings, Speeches, and Interviews. New York: Simon & Schuster.

Marinacci, Barbara, and Krishnamurthy, Ramesh, eds. (1998). Linus Pauling on Peace: A Scientist Speaks Out on Humanism and World Survival; Writings and Talks by Linus Pauling. Los Altos, CA: Rising Sun Press.

Mead, Clifford, and Hager, Thomas (2001). Linus Pauling: Scientist and Peacemaker. Corvallis: Oregon State University Press.

Newton, David E. (1994). Linus Pauling: Scientist and Advocate. New York: Facts on File.

Pauling, Linus (1958, 1983). No More War! New York: Dodd, Mead & Co.

Pauling, Linus (1964). "Modern Structural Chemistry." In Nobel Lectures Including Presentation Speeches and Laureates' Biographies, Chemistry 1942–1962. New York: Elsevier. Also available from <http://www.nobel.se/chemistry/laureates/>.

Serafini, Anthony (1989). Linus Pauling: A Man and His Science. New York: Paragon House.

Internet Resources

Pauling, Linus. "Science and Peace." Available from <http://www.nobel.se/peace/laureates>.