Few doctrines in Islam have engendered as much contention and disagreement as those surrounding the imamate, the office of supreme leader of the Muslim community after the death of the Prophet. In the medieval period while the caliphate still existed, rivalry among the claimants to that most lofty position was particularly intense. The early 5th/11th-century Ismaili da'i Hamid al-Din al-Kirmani worked for most of his life in the eastern lands of...