Scholars of Islamic legal studies can only be grateful for the continued presence and energy of [Modarressi]…In a nonornate style, Modarressi provides an account of the life and views of the eponym of one of Islam’s longest traditions of legal reasoning, and of how his example served as a basis for a school of law that can claim 200 million followers today—in Islam’s fifteenth century.

Jaʿfar al-Ṣādiq is a key figure in the formation of Shīʿī law, Hossein Modarressi’s expertise in the field is legendary, and the book brings together a trove of information that is otherwise scattered in a plethora of arcane sources.

This study constitutes an impressive and significant contribution to Islamic legal studies. It provides an unparalleled insight into the legal thought of the founder of the Jaʿfarī school, and can also serve as a reliable introduction to major aspects of Twelver Shīʿī law. The novelty of the approach, the wealth of information provided, the fine rendition of judiciously chosen texts, and the masterful elucidation and analysis of legal terms and concepts will all be of great value to students of the Islamic legal tradition.

This book represents a lifetime’s research and thinking about the legal thought of Jaʿfar al-Ṣādiq, one of the most important figures in the history of the Shīʿī tradition. Most broadly, it is a major contribution toward a better understanding of the formative history of Shīʿism, on the one hand, and of Islamic law in its first centuries, on the other. It will be the standard work of reference on early Shīʿism for many years to come.