The Ismāʿīlīs represent the second largest Shīʿī Muslim community after the Twelvers, and are today scattered throughout more than twenty-five countries in Asia, the Middle East, Africa, Europe and North America. The second edition of this authoritative book traces the history and doctrinal development of the Ismāʿīlīs from their origins in the formative period of Islam to the present day, a period of more than twelve centuries. It is the first comprehensive synthesis of the results of modern scholarship in Ismāʿīlī studies and draws on numerous primary sources on the subject, including the Ismāʿīlī manuscripts which have only recently become available. All the major phases of Ismāʿīlī history are covered, including the pre-Fāṭimid period, the Fāṭimid ‘golden age’, the Ṭayyibī-Mustaʿlī period and the history of the Nizārī Ismāʿīlīs of Persia and Syria before the Mongol invasions. The final part traces the history of the modern Ismāʿīlīs, particularly the socio-economic progress of the Nizārī communities. The new edition has been thoroughly revised and incorporates new material, an expanded bibliography and new illustrations. It will be invaluable reading for students of Islamic and Middle Eastern history.