ABŪ YŪSUF (AH 113–182/731–798 CE), more fully Yaʿqūb ibn Ibrāhīm al-Anṣārī al-Kūfī; Islamic jurisconsult and, with Muhammad ibn Hasan al-Shāybanī (d. AH 189/805 CE), one of the founders of the Ḥanafī school of law. Abū Yūsuf flourished at a time of transition, when legal doctrine was still being formulated independently of the practice of the courts by groups of idealistic religious scholars in geographically determined schools. At the same time, individual scholars were appointed qāḍīs, or judges, by the government, especially under the Abbasids, who fostered a policy of official support for the religious law. The period also coincided with the beginning of the literary expression of technical legal thought. Abū Yūsuf's life and doctrines may be seen in the context of all these developments.

As a...