Over the course of the long and violent twentieth century, only a minority of international crime perpetrators ever stood trial, and a central challenge of this era was the effort to ensure that not all these crimes remained unpunished. This required not only establishing a legal record but also courage, determination, and inventiveness in realizing justice. Defeating Impunity moves from the little-known trials of the 1920s to the Yugoslavia tribunal in the 2000s, from Belgium in 1914 to Ukraine in 1943, and to Stuttgart and Düsseldorf in 1975. It illustrates the extent to which the language of law drew an international horizon of justice.