Paul Scheffer, Professor at the School of Humanities, Tilburg University is an influential figure surrounding the debate on diversity in the Netherlands. His book Immigrant Nations (Polity Press) published in is a major reassessment of how immigration is changing our world. The policies of multiculturalism that were implemented in the wake of post-war immigration have, especially since 9/11, come under intense scrutiny, and the continuing flow of populations has helped to ensure that immigration remains the focus of intense social and political debate. Based on his deep knowledge of the European and American experience, Scheffer shows how immigration entails the loss of familiar worlds, both for immigrants and for host societies. The conflict that accompanies all major migratory movements is not the result of a failure of integration, but is part of a search for new ways of living together. It prompts an intensive process of self-examination on all sides. Immigration has such a profound impact because it goes to the heart of institutions such as the welfare state and liberties like the freedom of expression; liberal democracies developing into immigrant nations go through an existential change. To cope with these challenges, Scheffer argues, we should move beyond multiculturalism and take a fresh look at the meaning of citizenship in a globalizing world.