This cutting-edge textbook is the most comprehensive introduction to international relations theory available. It argues that theory is central to explaining the dynamics of world politics, and includes a wide variety of theoretical positions, from the historically dominant traditions to powerful critical voices since the 1980s. The editors have brought together a team of international contributors, each specialising in a different theory. They each explain the theoretical background to their position before showing how and why their theories matter. The book opens up space for analysis and debate and leaves students to decide which theories they find most useful in explaining and understanding international relations. The book is supported by an Online Resource Centre. Student resources: Key points for each chapter Web links Flashcard glossary Lecturer resources: PowerPoint slides