This book analyzes the social capital of the growing knowledge economy. The theoretical part discusses social capital as an economic concept, its relation to traditional capital theory and its role as a spatial externality. A theory of the social capital of the enterprise is developed and social capital's importance for entrepreneurship, innovation and regional development is analyzed. The empicical part compare some central aspects of social capital of three different socio-economic systems: the US, Japan and Sweden, regarding labor market relations, innovation systems and the civil societies. The social capitals of the knowledge intensive biotech industries of the three countries are studied and compared. Finally, a number of issues for further research are discussed.