How are the same criminal cases judged under different European criminal law systems? In this book, five challenging Dutch criminal cases and accompanying Supreme Court judgments form both the starting point and the central steppingstone of a description and comparative analysis of the law on criminal participation in five prominent European countries. These cases concern disputable aspects of criminal regulations applicable to situations in which persons Act Together in Crime. All cases focus on joint perpetration, criminal aiding, or both, and their outcomes have provoked (strong) debates among legal scholars and practitioners in the Netherlands. The book starts with a presentation of the cases, followed by an extensive overview of the Dutch law on criminal participation. Then, criminal law experts from France, Germany, Austria and Italy each present their nation's law on joint perpetration and criminal assistance, and their analyses of the five cases. The book concludes with an overall comparative perspective of the different outcomes to the cases and a reflection on the different systems of criminal participation in the pre-mentioned countries. This study seeks to give legal scholars, practitioners and lawmakers a valuable insight in the differences and similarities in how five important European criminal law systems deal with one of the most challenging criminal law topics. This research was carried out by a network of experts from Austria, France, Germany, Italy and the Netherlands and is edited by Laura Peters. She is Assistant Professor of Criminal Law at the University of Groningen, the Netherlands and publishes regularly on comparative criminal law issues.