First Paragraph: The history of the revolutionary movement of the ʿAlid Muḥammad ibn ʿAbd Allāh ibn al-Ḥasan ibn al-Ḥasan with his messianic claim of Mahdīship has long attracted the interest of Amikam Elad, and he has published a number of scholarly studies on aspects of it. In the present book, he presents a comprehensive and wide-ranging examination of what he portrays as a rebellion of one branch of the Prophet Muḥammad’s Hāshimī kinship, the ʿAlids, against another branch, the ʿAbbāsids, who had recently established their rule of the Muslim world as caliphs by overthrowing the Umayyad caliphate. Elad bases his history on a collection of the vast amount of relevant Muslim historical reports of both backers and opponents of the rebellion and meticulous analysis of their chains of transmission as well as their contents. Although he rejects many of them as outright forgery or tendentious invention, he accepts some as reliable source material that can be used to reconstruct the course of the events leading up to the bloody conflict and failure of the rebellion.