Judge Mettraux's four-volume compendium, International Crimes: Law and Practice, will provide the most detailed and authoritative account to-date of the law of international crimes. It is a scholarly tour de force providing a unique blend of academic rigour and an insight into the practice of international criminal law. The compendium is un-rivalled in its breadth and depth, covering almost a century of legal practice, dozens of jurisdictions (national and international), thousands of decisions and judgments and hundreds of cases. This first volume discusses in detail the law of genocide: its definition, elements, normative status, and relationship to the other core international crimes. While the book is an invaluable tool for academics and researchers, it is particularly suited to legal practitioners, guiding the reader through the practical and evidential challenges associated with the prosecution of international crimes.