Isay, Ernst Keywords: Nationality | Mots clefs: Nationalité | ABSTRACT After an introduction to the State and the personal and territorial elements of its definition, Ernst Isay focuses on the concept of nationality. The author then examines the issues of acquisition and loss of nationality, followed by the effects of nationality: the rights of nationals, the obligations of nationals, and the effects of nationality in private, criminal, and administrative international law. Après une introduction consacrée à l’État et à l'élément personnel et territorial de sa défi…