Professor of Political Science at the University Pompeu Fabra (Barcelona). His main research interests revolve around the contexts of cultural diversity, especially the relationship between democracy, citizenship and immigration. Director of the Research Group on Immigració Interdisciplinari (GRITIM-UPF). Currently working on a political theory of borders. He has published numerous books, articles and chapters in national and international journals. The latest two are minority nations Immigration (2008) and political concepts in the context of Spain (2007).