Until recently the Isma'ilis were judged almost exclusively on the basis of the hostile accounts of their Muslim enemies and the fanciful tales of the Crusaders. As a result, numerous misconceptions were disseminated about the teachings and practices of the Isma'ilis, known in European tradition as the Assassins. In the 1930s, however, authentic Isma'ili texts began to be recovered from private collections which shed new light on mediaeval Isma'ili history and thought. This collective volume, the first major effort of its kind in this branch of Islamic studies, brings together some of the original results of modern scholarship in the area, written by leading contemporary authorities, as well as distinguished Islamists.