The toleration of dual citizenship has become a global trend as states try to retain ties to their emigrants or to encourage their immigrants to naturalise. This volume examines changes in state attitudes to dual citizenship and their social impact, zooming in from analyses of global dynamics to a series of country case studies that illustrate the variety of reasons and intentions behind dual citizenship reform. Finally, five chapters provide the most thorough analysis of the special Austrian case so far. They show the size of Austria’s untapped potential for naturalisation of immigrants, the incoherence of its citizenship policies at home and abroad and the need for a comprehensive reform.