Almost everyone has citizenship, and yet it has emerged as one of the most hotly contested issues of contemporary politics. In this volume, prominent citizenship theorist and legal scholar Peter J. Spiro explains citizenship through accessible terms and questions: what citizenship means, how you obtain citizenship (and how you lose it), how it has changed through history, what one receives from citizenship, and what entitles a person to citizenship, including dual citizenship and naturalization. Spiro provides historical and critical perspective to a concept that is a part of our everyday discourse, providing a crucial contribution to our understanding of a central organizing principle of the modern world.