International relations is a discipline dominated by the debate between the realist and idealist paradigms. This book provides the most comprehensive critical review of the realist tradition to date. The dominant realist tradition in the study of international politics explains interstate behaviour in terms of the fundamental difference between domestic' and international' forms of government. This approach underlies the grim view that, beyond the borders of sovereign presence, politics is not about potential moral progress, but survival. This book argues that political realism is not a meaningless term, but that the work of Hans Morgenthau and Kenneth Walz, two of the key grand theorists', could more properly be associated with the idealist model. By critically evaluating the work of Morgenthau, Walz and Hedley Bull the author provides a reinterpretation of the terms realism' and idealism'.