This book is the result of a project elaborated in cooperation between the IMPEL working group on criminal prosecution and METRO, with the goal of providing an insight into the systems and methods of criminal prosecution in environmental cases in practice. This book therefore provides an overview of criminal prosecution practice in environmental cases in Austria, Belgium, Denmark, Finland, Germany, Italy, the Netherlands, Portugal, Spain and the United Kingdom. It is based on the results of a comprehensive questionnaire that was answered by various experts in country reports. In addition, the book contains a detailed summary and comparison of the country reports. This provides not only a summary of the criminal prosecution of environmental law in the various countries, but also addresses differences and similarities in practice with respect to environmental criminal law. A critical analysis of the answers is also provided.