This book presents the results of a research project on judicial protection in transnational criminal proceedings that has been funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – project number: BO 2499/4-1. Based upon a comparative analysis of the national criminal justice systems of eight European countries, the study seeks to identify shortcomings in judicial protection and outlines a comprehensive framework for judicial protection in transnational criminal proceedings that would ensure the right to judicial review without hampering the effective functioning of international cooperation in criminal matters. The book examines a broad range of potential approaches in the context of selected national criminal justice systems and offers a comparative analysis of EU Member States and non-Member States alike. The book particularly focuses on the differences between cooperation within the EU on the one hand and cooperation with third states on the other and on the consequences of this distinction for the scope of judicial review.