Sageman sets out to explain why people with radical political agendas turn to violence. He covers the French Revolution, the development of terrorism in tsarist Russia, the radical nationalist movements in the Balkans that helped trigger World War I, and anarchist violence in the United States during the early twentieth century. The book’s greatest value lies in its detailed accounts of the individuals who plotted attentats (Sageman favors this French word over “attacks” because it better conveys a sense of aggression). Although the book touches on mob violence and indiscriminate killing, Sageman mostly examines efforts to assassinate significant political figures. His sharp focus on the perpetrators of such acts illuminates their motives and circumstances but does not contribute much to Sageman’s main goal of developing a general theory of why some people become killers. One thing that comes through quite clearly, however, is the role of political repression in radicalizing those who might otherwise have eschewed violence.