This book fills a major gap in the scholarly literature concerning international criminal law, comparative criminal law, and human rights law. The principle of legality (non-retroactivity of crimes and punishments and related doctrines) is fundamental to criminal law and human rights law. Yet this is the first book-length study of the status of legality in international law in international criminal law, international human rights law, and international humanitarian law. This is also the first book to survey legality/non-retroactivity in all national constitutions, developing the patterns of...