This book presents the Balanced Development Index (BDI), measuring socioeconomic development in twenty-two European OECD member countries in a period 1999-2017. Compared to other composite measures of development, BDI looks beyond traditional development indicators, such as GDP, to create an index which gives equal weight to social, economic, objective, and subjective aspects of development. The BDI aggregates forty-two detailed indicators into four composite middle-level indexes: external economic (characterizing functioning of national economies in their international surroundings), internal economic (characterizing various aspects of domestic economic conditions), social expectations (public hopes and fears concerning economic, political and social conditions), and current social condition (including both objective and subjective social indicators)—which are, in turn, aggregated into the general BDI index.