Is there a common ground on which a European citizenship can be constructed? This volume looks at four foundations of citizenship in Europe: the legacy of national identities, current designs and projects for social and political citizenship in Europe, a transitional public space as the basis of an active European Citizenship in Europe, and a transitional collective identity as a symbolic boundary marker for European citizenship. Such options raise the theoretical question of how to conceive citizenship in a transnationalizing world. Since the idea of European citizenship cannot escape the problem of defining who is a European citizen and who is not, the theoretical problem is tackled by defining the collective bonds of European citizens beyond primordial or traditional bonds that have dominated European history.