Magnificent castles and fortresses in remote, mountainous regions were built for refuge and defensive purposes by the Ismaili Muslims of Iran and Syria fleeing from persecution during the early middle ages. Often superior in construction to those built by the Crusaders, these castles withstood numerous offensives for over two centuries until the middle of the thirteenth century when most were captured and demolished by the Mongols. Peter Willey describes the discoveries he made during the course of more than 20 expeditions to these Ismaili sites spanning the past forty years. The book is illustrated with photographs, maps and plans. As well as being a piece of original scholarship, it is also a readable personal account of the challenges encountered in expeditions to remote, inaccessible and often hazardous locations.