Al-Kashshāf (Commentary) is among the most widely known tafsirs (explications or exegeses) of the Qur’an. Written in 12th-century Persia by Mahmud ibn ʻUmar Zamakhshari, it remains the object of study and debate among exegetes, who argue against its Mu’tazilite rationalism, even as they recognize its deep learning and linguistic sophistication. The work is taught, if not admired, by all the Sunni and Shia schools of interpretation. Modern scholar Kifayat Ullah states that “no other work in the history of tafsir has been commented on in the forms of glosses, superglosses, supercommentaries, and mukhtasars [abridgements] more than al-Kashshaf.” The breadth and complexity of the arguments are summarized in the book’s subtitle: “On the mysteries of revelation, the perfection of locution, and comprehensive interpretation [of the Qur’an].” Mu'tazilism’s rational approach to the nature of God and scripture passed from the mainstream of Muslim thought in much of the Islamic world, but it survived in the area of Khurasan (also seen as Khorasan), Iran, the home of Zamakhshari. The author’s challenge to orthodox philosophy, combined with his undisputed mastery of Arabic grammar and philology and his extensive travel to promote his ideas, provided the foundation for the enduring legacy of his tafsir. The work was printed in two volumes in 1864 at the Bulaq Press in Cairo, at the time under the administration of ‘Abd al-Rahman Rushdi and under the scholarly direction of Shaykh Muhammad Qutb al-‘Adawi. The work was edited by Muhammad al-Sabbagh, who may be the author of the notes in the margin of the main text. There is a biographical and critical afterward in rhymed prose, including panegyric poetry and the text of the inscription on the author’s grave in eastern Iran.