International relations is a vibrant field of significant growth and change. This book guides students through the complexities of the major theories of international relations and the debates that surround them, the core theoretical concepts, and the key contemporary issues. Introduced by an overview of the discipline's development and general structure, the more than 40 entries are broken down as follows: Part two introduces the key theories and each chapter includes: a broad overview; a discussion of methodologies; a review of empricial applications; and a guide to further reading and useful websites. Part three discusses the major concepts and for each concept provides: an introduction to the core questions; an overview of the definitions and theoretical perspectives; a review of empirical problems; and links to other entries, further reading and useful websites. Clear and highly readable, "Key Concepts in International Relations" is an essential guide for students on politics and international relations courses.