This book examines the fascinating story of how the chief architects of realism (Hans Morgenthau, Kenneth Waltz and John Mearsheimer) dealt with some of the most pressing political issues of our time through the lenses of fear. Pashakhanlou conducts the most comprehensive evaluation of their works to date, compromising of a meticulous analysis of 400 of their publications. As such, this book is an invaluable resource for practitioners, students and concerned citizens that seek to understand how three of the most influential International Relations scholars thought about the implications of fear at the global level. 'In this important book, the author gets to the heart of the underlying emotional condition on which so much rational political thought in International Relations is built. By uncovering the role of fear within the modern classics of realism, the book sheds light on the role that fear plays in producing otherwise rational decision-making.' David Galbreath, Professor of International Security, University of Bath, UK 'The role played by fear in Realist international theory is under-explored and poorly theorised. This book addresses this lacuna and provides a thorough and systematic analysis of the significance of fear in Realism. In doing so, Arash Heydarian Pashakhanlou makes a major contribution to International Relations theory, and the 'emotional turn' in the study of contemporary international politics'. Adrian Hyde-Price, Professor of International Politics, Gothenburg University, Sweden.