The book identifies the main theories proposed in the field of terrorism studies as they relate to several issues: why and how individuals and organizations get involved in terrorism; the definition and concept of terrorism; state terrorism; leaving terrorism behind; counter-terrorism; manifestations of terrorism in time and space.Terrorism studies is a highly heterogeneous field with a broad range of theories and disciplines, marked by ample debates. Beyond individual contributions and unique perspectives, however, it is difficult for students and interested readers to have a broader and structured grasp of the theoretical landscape within and behind the study of terrorism. This textbook offers a valuable new teaching tool which aims to provide students with the conceptual, theoretical, and methodological toolbox necessary to understand and research terrorism.This book will be essential reading for students of terrorism studies, political violence, and counter-terrorism, and is highly recommended for students of security studies, criminology, politics, and international relations.