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 theorising of citizenship. Providing a comprehensive analysis of the subject, the book 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 analyses the ius doni concept in both international law and EU law, further tests its application in practice and establishes best practices among states. Finally, the book discusses the conceptual and practical implications for citizenship.