This book provides a short, comprehensive and accessible introduction to Ultra-Realism: a unique and radical school of criminological thought that has been developed by the authors over a number of years. After first outlining existing schools of thought, their major intellectual flaws and their underlying politics in a condensed guide that will be invaluable to all undergraduate and postgraduate students, Hall and Winlow introduce a number of important new concepts to criminology and suggest a new philosophical foundation, theoretical framework and research programme. These developments will enhance the discipline's ability to explain human motivations, construct insightful representations of reality and answer the fundamental question of why some human beings risk inflicting harm on others to further their own interests or achieve various ends. Combining new philosophical and psychosocial approaches with a clear understanding of the shape of contemporary global crime, this book presents an intellectual alternative to the currently dominant paradigms of conservatism, neoclassicism and left-liberalism. In using an advanced conception of "harm", Hall and Winlow provide original explanations of criminal motivations and make the first steps towards a paradigm shift that will help criminology to illuminate the reality of our times. This book is essential reading for academics and students engaged in the study of criminology, sociology, criminological theory, social theory, the philosophy of social sciences and the history of crime.