This two-volume set presents a comprehensive selection of some of the most significant published papers and articles on terrorism. The collection examines terrorism from a variety of perspectives, including state terror. Beginning with a section on concepts of terrorism, it first considers the causes and nature of regimes of terror. It then concentrates on terrorist groups in society and in a search for explanations, it investigates the relationship between terrorism and religion, the underlying causes for the rise of terrorist groups and the relation of these groups to new social movements. Psychological and rational choice explanations are also explored. Several articles study the organization of terrorist groups and their strategy and tactics. A final section deals with methods of counteracting terrorism.The editor has written an authoritative introduction which highlights the centrality to terrorism of the killing of innocents and draws important lessons from the topics covered in the collection.