Terrorist violence can often seem both irrational and indiscriminate. This book is an attempt to describe why terrorists attack particular targets. Looking at terrorist groups from around the world, and over the past 100 years, it examines the nature of terrorism and the various factors which influence terrorists' target selection. In particular it looks at the influence of the ideologies, strategies and tactics of terrorist groups, and describes how these are restricted by the terrorists' resources, by security and anti-terrorist measures, and by society within which the terrorists operate. The book also shows how target selection can be affected by the nature of the terrorists themselves and by their supporters. Overall it concludes that apparently irrational and indiscriminate terrorist attacks are frequently the result of factors which are both explicable and logical.