In Ius Doni in International Law and EU Law, Dr. Christian H. Kälin establishes the concept of ius doni in the contemporary legal and political theorizing of citizenship. Providing a comprehensive analysis of the subject, it discusses the legal and political concepts of citizenship. It also introduces a new term for what is already an increasingly common and accepted practice of granting citizenship on the basis of substantial contributions to the state. Consisting of two main parts – law and practice – the monograph analyzes the concept of ius doni in both international law and EU law, tests its application in practice, and seeks to establish how it can be used to govern best practices among states. Finally, the book discusses the conceptual and practical implications that ius doni has for citizenship more generally.