Ed. Alette Smeulers. Extreme forms of collective violence such as genocide, crimes against humanity and war crimes can endanger international peace and security. The international criminal justice system has been set up in order to prosecute these crimes and to thus restore international peace and security. These crimes are however extremely complex social phenomena and it takes an inter- and multidisciplinary approach to understand the true nature of this type of criminality and to effectively prosecute the perpetrators thereof. This book enhances our knowledge of these complex phenomena and thus contributes to a better and more effective system of international criminal justice. Scholars from many different scientific disciplines such as law, criminology, political science, psychology, research methodology and information technology as well as practitioners from within the field have contributed to this book. General themes in the book are: What kind of people are perpetrators of collective violence? How can we attribute criminal responsibility to individuals for crimes which are collective in nature? How can we study these crimes and how can we discover patterns of violence? What role can statistics play when holding individuals accountable? How to develop strategies of prosecution? What difficulties do prosecutors and judges face and how important and useful is the ICC Case Matrix? These are just a few of the many questions addressed in this book.