Assassins are the followers of a Shia Islam sect that imposed terror on the Muslim world and in Europe for two centuries (the 11th and 12th centuries CE) - through acts of terror and murder of political and religious opponents. Their name in English and French and other languages became over time a synonym for political murderers and money seeking killers. This book by Lewis is an important and timely academic research on the Assassins sect and is the first edition to be published in Hebrew. This research can assist in understanding the ways in which religious- political groups managed to make a violent and extremist turn in the fundamental relationship between religion and state, and how they used violence to achieve their objectives.