From war, terrorism and weapons of mass destruction, through environmental and economic crises, to epidemics, cyber-war and piracy, the twenty-first century world seems beset by a daunting range of international security problems. At the same time, the academic study of security has become more fragmented and contested than ever before as new actors, issues and theories increasingly challenge traditional concepts and approaches. This innovative new text focuses on the politics of international security: how and why issues are interpreted as threats to international security and how such threats are managed. After a brief introduction to the field and its major theories and approaches, the core chapters systematically analyze the major issues on the contemporary international security agenda. Each is examined according to a common framework that brings out the nature of the threat and the responses open to policy makers.