Few social scientific concepts have gathered so much attention and so many followers in such a short period of time than the concept of social capital. As the articles collected in the current volume show, the fundamental idea can be traced back at least to de Tocqueville ([1840] 1945, Chapter 1 in this volume). Hanifan (1920, Chapter 2 in this volume), Jacobs (1961, Chapter 4 in this volume), ...