This unique book brings together leading experts from diverse areas of public international law to offer a comprehensive overview of the approaches to evolutionary interpretation in different international legal regimes. It begins by asking what interpretation is, offering the views of expert authors on the question, its components and definitions. It then comments on situations that have called for evolutionary interpretation in different international legal regimes, including general international law, environmental law, human rights law, EU law, investment law, international trade law, and how domestic courts have, on occasions, interpreted treaties and other international legal instruments in an evolutionary manner. This timely, authoritative compendium offers an in-depth understanding of the processes at work in evolutionary interpretation as well as a prime selection of the current trends and future challenges.