Over the past fifty years, local government in Europe has been confronted with escalating scales of production, population migration and market pressures. These developments have complicated its performance, challenged its domain and even threatened its existence. A popular coping strategy is inter-municipal cooperation, a phenomenon that, despite its ubiquity, has not been subject to systematic comparative research. This book presents an overview of inter-municipal cooperation in eight European countries. Each country study sketches its attendant forms, their institutional design, the tasks and competencies attributed to joint authorities of municipalities and the way inter-municipal cooperation operates in practice. Both performance and democratic aspects of cooperation are recurring topics. The last chapter of the book presents a comparative analysis and reflects on the future of inter-municipal cooperation.