The article introduces a new way to classify how different regions are governed in OECD countries. They group them into four categories: planning regions, co-operative regions, regions with decentralized government, and regions with legislative powers. This helps us understand the various types of regional governance worldwide, their goals, the problems they aim to solve, and the challenges they face. The article also talks about other bodies and tools that might exist at the regional level, like representatives from the central government, regional development agencies, and metropolitan governance bodies.