This textbook introduces students to the study of contemporary international security. It is aimed at second and third year undergraduates as well as postgraduate students undertaking a taught Masters degree programme. Eschewing jargon, this textbook is clear and accessible; with pedagogical features such as boxes, key points, further reading and student questions. Key theories and concepts are presented in the introductory chapters, and applied to the case-studies and empirical examples in subsequent chapters. Its strong empirical dimension allows it to illustrate contemporary international security problems and issues. The book will be essential reading for upper-level students of international or global security studies, and recommended reading for students of strategic studies, war and conflict studies, terrorism studies and IR in general.