JAʿFAR AL-ṢĀDIQ (AHd. 148/765 CE) is one of the leading figures in early Islam expounding the teachings from the family of the Prophet. Active in Medina's scholarly circles, where he was born in 699 or 703, Jaʿfar al-Ṣādiq was the most frequently cited authority on points of law and tradition. His father, Muḥammad al-Bāqir, was an established scholar in Medina's learned circles. Jaʿfar al-Ṣādiq transmitted his family's wisdom to Muslims of diverse backgrounds and exponents of other religions, theosophers as well as Gnostics, who frequented his house in quest of knowledge.

In Shīʿī tradition, Jaʿfar al-Ṣādiq is a central figure and the last common imām recognized by both the Ithnāʿasharīs and the Ismāʿīlīs. After his death, the Shīʿī imām...