This book examines how the academic discipline of International Relations has conceptualized the world historical crisis that has shaped world affairs between the end of the First World War and the end of the 1990s. A distinguished group of contributors trace the development of the subject through the main historical periods and in relation to key debates: ethics, power and nationalism; conditions of peace; law and peaceful change; and globalization. It provides the most comprehensive survey of the discipline's past and the key issues to be faced in the future.