In many fields, enforcement of EU policies is performed by the Member States. In principle, Member States are free to decide how and by which means they enforce such policies, albeit under the observance of EU legal principles and harmonised rules. While differences between Member States are inevitable, especially at the interface of criminal and administrative enforcement, they should not create legal obstacles to effective and rule of law-based enforcement in cross-border cases. In his dissertation, Aart de Vries analyses the legal principles and rules that determine the gathering, sharing, and use of evidence by EU Member States’ administrative and judicial authorities in cross-border enforcement cases to answer an important and current question: do these legal principles and rules enable effective and rule of law-based transnational punitive enforcement of EU policies? De Vries looks into supranational EU law and national law in The Netherlands, Germany, and France to provide a detailed analysis of the applicable legal framework. On the basis of his findings, De Vries presents a convincing answer to the aforementioned question and puts forward various recommendations to enhance transnational punitive enforcement in the EU. In this light, this dissertation provides insights for academics and practitioners with an interest in punitive (criminal and administrative) enforcement of EU law. Evidence and Transnational Punitive Enforcement Proceedings in the European Union is part of the Pompe series; publications that combine legal and social-scientific approaches to the problems of criminal law, written by staff members of the Willem Pompe Institute for Criminal Law and Criminology in Utrecht and by authors who share the Institute’s school of thought. Its central theme is the protection and enforcement of fundamental rights in a changing world, focussing on the position of vulnerable groups in relation to the state and on the significance of individual human rights in an international context.