Sūfīs (for suggested etymologies, see TAṢAWWUF). Muslims who seek close, direct, and personal experience of God, and who are often, therefore, described as mystics. Sufism is usually treated as a single phenomenon, although it is made up of different strands and styles. Sufism is a major part of Islam, and Sūfīs have been particularly important in the spread of Islam. By the 18th/19th cent. CE, at least a half (perhaps as many as three-quarters) of the male Muslim population was attached in some sense to a Sūfī ṭarīqa (order). Thus although Sufism has often been contrasted with the forms of Islam concerned with fīqh and sharīʿa (i.e. with the lawful ordering of Muslim life), and although there have historically been clashes between the two, there is no inherent or necessary conflict: Sūfīs in general have been insistent on the necessity for the proper observance of Islam (examples are al-Muḥāsibī and his pupil al-Junaid, who is known as ‘the father of sober Sufism’) and have themselves been critical of antinomian tendencies or individuals in Sūfī movements—associated e.g. with Khurasān, or with the Qalandars. The union between Sūfī devotion and sharīʿa is associated particularly with al-Ghaz(z)ālī and the great Indian teacher, Aḥmad Sirhindī (d. 1625 (AH 1034)): he was a Sūfī of the Naqshbandī order who affirmed that while the experience of the unity of all being in God is real, it is neither the whole nor the end of religion: moral and virtuous life are as important—and to enforce this he wrote letters to his many followers throughout India. The Sūfī experience of absolute reality (ḥaqīqa) is not opposed to sharīʿa but is its foundation.

The early history of Sufism is not yet clear. It seems to have emerged from a determination among some early Muslims not to be distracted by the rapid Muslim expansion over vast territories from the vision and practice of Muḥammad in realizing the absolute sovereignty of God in life. Of this early attitude, al-Ḥasan al-Baṣrī (Basra being an important centre of it) is a major example, and later Sūfī orders look back to him as a key link in the connection back to the Prophet. Also from Basra was the notable Rabiʿa al-ʿAdawiyya; but Sūfī devotion took root in many different places, often absorbing in each place something of its different atmosphere. Thus Khurasāni Sufism reflected its parched surroundings in an austere asceticism, producing such remembered figures as Fudayl ibn ʿIyad, Ḥātim al-Aṣamm (who left behind the four principles of Sūfī life, to remember that no one eats your daily bread for you, that no one performs your acts except yourself, that as death is hurrying toward you so address your life now to meet it, and that every moment of your life is under the eye and judgement of God), and Ibrāhīm ibn Adham. The latter was a prince who experienced a dramatic conversion when out hunting.

Or again Kashmiri Sufism, from the 14th cent. onward, drew on Hindu asceticism, even producing an order, the Rishis, whose name was derived from the word ṛṣi (understood as ‘a singer of sacred songs’).

Since Sufism was a commitment to God in absolute trust and obedience, it (unsurprisingly) gave rise to intense experience of that relationship. Techniques were developed (e.g. dhikr, samaʿ) which were capable of producing trance states of ecstasy. The realized condition of union with God produced such a sense of the absolute truth of God, and of the bliss of union with him, that poetry and teaching began to emerge in which the distinction between God and the self seemed to be blurred—or even obliterated: the disturbance this caused for those sensitive to the absolute transcendence of God can be seen in the fate of al-Ḥallāj, although far more threatening in effect was the mystically monistic system of ibn al-ʿArabī. Any potential conflict between the ʿulamā and the Sufis was largely overcome by the work of al-Ghaz(z)ālī, who knew both positions at first hand, and demonstrated the part that both play in Islam.

From the experience of devotion to God, the Sūfī poets, especially in Persia, produced works of enduring beauty and power. Among the earliest was Pīr-i-Anṣār (ʿAbdullah al-Anṣārī, d. 1088 (AH 481)), of Herat in Khurasān.

Other memorable poets were Farīd al-Dīn ʿAṭṭār, ibn al-Fāriḍ, Jāmī, and perhaps consummately Jalāl al-Dīn Rūmī.

The wide extent and influence of Sufism led to attempts being made to give systematic order to its teachings and techniques—a notable example being Ali Hujwīrī (d. 1702). But even more important was the organization of Sūfī traditions into formal orders (tarīqa, pl. turūq; silsilah). For examples, see CHISHTI; MAWLAWIY(Y)A; NAQSHBANDIY(Y)A; QĀDIRIY(Y)A; SHĀDHILIY(Y)A. An adherent is known (in general terms, though these words also have a wider use) as derwīsh, faqīr, marabout.

A leader is known as shaykh.