Whereas international migration, ethnic and ethno-national identities and citizenship issues have mainly been discussed separately or two by two (migration and citizenship, citizenship and national identity, etc.) in academic literature, this book attempts to discuss them jointly in a triangular analysis. Migration and the ways in which it is socially constructed constitute a lens through which we can look at both citizenship and ethno-national identity in order to renew these concepts and to increase their explanatory power in a rapidly changing world. The chapters collected in this volume attempt to do so in the context of the European Union. Beyond their theoretical diversity, the authors address, in one way or another, the relationship between migration, ethno-national identities and citizenship issues. Some of them take an empirical perspective while others elaborate quite sophisticated theoretical constructions. Some papers deal strictly with the European Union as such, while others deal with single member states or even with non-EU countries. Some chapters are purely sociological while others have a viewpoint from political science, history or linguistics. But the willingness not to disconnect the three sets of issues addressed appears clearly as a major methodological standpoint in each contribution, even though each author stresses its specificity.