Essentials of Terrorism: Concepts and Controversies is a concise resource for understanding modern terrorism. This briefer version of Martin’s popular text Understanding Terrorism, Second Edition, can be readily used in conjunction with other resources such as Martin’s The New Era of Terrorism collection of readings, or with other supplemental texts or journal articles. The content of Essentials of Terrorism: Concepts and Controversies is directed to academic and professional courses of instruction whose subject areas include terrorism, homeland security, international security, criminal justice administration, political conflict, armed conflict, and social movements. It can also be incorporated into academic conferences and professional training seminars covering international and homeland security studies, criminal justice administration, the attributes of terrorism and extremism, conflict resolution, and related subjects of inquiry. The intended level of instruction is flexible: As a stand-alone text, it is suitable for introductory undergraduate classes. When used in conjunction with other resources, the level of instruction can be adapted to upper-division undergraduate and master’s-level classes. If used in conjunction with professional manuals, Essentials of Terrorism: Concepts and Controversies is suitable for professional practitioners who require instruction in understanding terrorism.