At a time when issues concerning migration and the formation of diasporic communities have come to be critical for all European legal systems, this volume reflects, discusses and analyses the questions raised by diasporas who have established themselves in Europe over more than fifty years of immigration, and the challenges faced by legal systems in the light of continued migration. Contributors from a broad range of backgrounds thereby address prominent issues ranging from legal pluralism among minorities, pressures on EU accession states, irregular migration, state control of family reunification and formation in light of human rights laws, challenges for citizenship and nationality laws, the implementation of visa rules, and juxtaposed control zones. Besides the EU as a supranational legal order, the book contains discussion of conditions in the United Kingdom, Ireland, France, Spain, Gibraltar, Morocco, Greece, Turkey, and Lithuania. This volume accompanies "The Challenge of Asylum to Legal Systems" and is the second book to emerge from the W. G. Hart Legal Workshop held in 2004 at London's Institute for Advanced Legal Studies.