This text presents the Chapter on Satan (Bab al-shaytan) from an Ismaili work called the Kitab al-Shajara by the 4th/10th-century Khurasani da'i, Abu Tammam. The satans of Tammam’s Chapter are the founders and instigators of the 72 heretical sects of Islam. Each sect has been accorded a relatively lengthy description as perceived from a generally Shi'i and Mu'tazili point of view. The volume contains both a critical edition of the Bab al-shaytan and a complete English translation of it.