This introduction presents an overview of the key concepts covered in the subsequent chapters of this book. The book outlines the regional economic planning in the European Community and describes the revolution in regional studies that has paralleled and contributed to the regional interventionist movement. It reviews regional development theories and their contribution to the understanding of the causes and nature of spatial variations in prosperity. The book also focuses on interregional theory and its implications for Community expansion, after which attention turns to intraregional theory and the role of private and public sectors in the development process. It also charts the rise of regional policies, considers the methods employed in the attempt to correct major imperfections in the development surface and compares national strategies with those of the Community. It then explores the question of policy assessment, the difficulties inherent in the assessment process and the prospects for further progress in an expanding Community experiencing severe recession.