This introductory chapter provides an overview of the rise of dual citizenship. For most of the twentieth century, citizenship was an exclusive bond between an individual and a state. Countries refused to share their citizens with other countries just like they do not share their territories. Since the 1990s, however, the principle of exclusive citizenship has been abandoned, and dozens of countries moved to permit dual citizenship. Today, toleration of multiple citizenship has become the norm, and tens of millions of persons around the world hold citizenship in two—sometimes even three or four—countries. The legitimation and proliferation of multiple citizenships is creating new realities on the ground, reshaping patterns of international migration, political participation, global security, and ethnic relations. Previous studies mostly examined dual citizenship in the context of immigration to Western Europe and North America. This book focuses instead on the strategic acquisition of dual citizenship by nonimmigrants from outside the West. Once one shifts the empirical focus, a crucial but overlooked aspect comes into sharp relief: the disparity in the value of the “citizenship packages” that different countries offer, and the tremendous practical usefulness that a second citizenship from a more developed country may provide.