In the history of Islamic esotericism, Ṣā'in al-Dīn 'Alī ibn Muḥammad Turka Iṣfahānī (d. 830/1427) was a thinker of extraordinary originality whose mystical thought played a formative and fundamental role in the development of later Islamic theosophical doctrines. As S. H. Nasr points out, 'in his integration of illuminationist theosophy with Peripatetic thought and philosophical mysticism (‘irfān)’, he is ‘perhaps the most important figure in Islamic philosophy after Naṣīr al-Dīn Ṭūsī, figuring as the key link in the chain [of philosophical thought stretching] between Mullā Ṣadrā, Suhrawardī and Ibn Sīnā.’ The profound originality of Ṣa'in al-Dīn's Persian prose style, Nasr adjudicates, ‘puts him in the same rank as Nāṣir-i Khusraw, Suhrawardī, Bābā Afḍal, Naṣīr al-Dīn Ṭūsī and Quṭb al-Dīn Shīrāzī.’ Author of some thirty books and treatises in Arabic and Persian, he is yet another major Persian philosopher who awaits Western discovery, research, translation and recognition. None of his works have to date been translated into any European language.
Born circa 761/1360 in Iṣfahān, Ṣā'in al-Dīn spent his youth travelling through Syria, Egypt and the Ḥijāz in pursuit of learning. It is recorded that as part of Tīmūr's (Tamerlane) enforced intellectual brain-drain of Iṣfahānī intellectuals, he was apparently forcibly transported from his native city to Samarqand together with his older brother in the latter quarter of the 8th/14th century, although he managed to return to Iṣfahān after Tīmūr's death in 1405. It is known that he learned the fundamentals of jurisprudence at the hand of this same older brother, who was a juridical authority.