The end of the cold war has provoked an explosive increase in theories, concepts, and debates in the discipline of international relations. There is growing confusion as to what are the important issues and what are the best ways of approaching them. This highly successful textbook provides a systematic introduction to the principle theories in international relations. It combines incisive and original analysis with a clear and accessible writing style, making it the ideal textbook for all students taking an introductory course in international relations or international relations theory. The book focuses on the main theoretical traditions - Realism, Liberalism, International Society, and theories of international political economy. The third edition includes two new chapters on Social Constructivism and foreign policy. Emphasis is placed on the relationship between IR theory (academic knowledge of IR) and IR practice (real world events and activities of world politics). The authors carefully explain how particular theories organize and sharpen our view of the world.