Nasseh Ahmad Mirza 
Syrian Ismailism [PDF ebook] 
The Ever Living Line of the Imamate, A.D. 1100–1260

This book is a welcome addition to an all too scant literature on the Ismaili communities of Syria. In addition to a wide reading of Arabic sources and a deep familiarity with the existing scholarly literature, Professor Mirza also brings to light new manuscripts illuminating this history.
Syrian Ismailism tells the little-known story of the adaptability and survival of Ismailis in Syria in an era which seems as complex and difficult as our own. The late eleventh and twelfth centuries brought severe troubles, including the decline of the Fatimids, divisions among the Ismailis, the Saljuq-Sunni conquest of much of the Middle East, and the Crusades.