Political realism dominated the study of international relations during the Cold War. Since then, however, its fortunes have been mixed: pushed onto the backfoot during 1990s, it has in recent years retuned to the centre of scholarly debate in international relations. Yet despite its significance in international relations theory, realism plays little role in contemporary international political theory. It is often associated with a form of crude realpolitik that ignores the role of ethical considerations in political life. This book explores an alternative understanding of realism. The contributors view realism chiefly as a diverse and complex mode of political and ethical theorising rather than either a value-neutral branch of social science or the unreflective defence of the national interest. They analyse a variety of historical and philosophical themes, probing the potential and the pathologies of realist thought. A number of the chapters offer critical interpretations of key figures in the canon of twentieth century realism, including Hans Morgenthau, E. H. Carr, and Reinhold Niebuhr. Others seek to widen the lens through which realism is usually viewed, exploring the writings of Martin Heidegger, Hannah Arendt, and Leo Strauss. Finally, a number of the contributors engage with general issues in political theory, including the meaning and value of pessimism, the relationship between power and ethics, the role of normative political theory, and what might constitute political 'reality.' Straddling international relations and political theory, this book makes a significant contribution to both fields.