Since the adoption of the Rome Statute of the International Criminal Court in 1998, international criminal law has rapidly grown in importance. This three-volume treatise on international criminal law presents a foundational, systematic, consistent, and comprehensive analysis of the field. Taking into account the scholarly literature, not only sources written in English but also in French, German, Italian, Portuguese, and Spanish, the book draws on the author's extensive academic and practical work in international criminal law. This second volume offers a comprehensive analysis of the core international crimes, namely, genocide, crimes against humanity, war crimes, and aggression. It also assesses relevant treaty crimes. It examines in detail the problem of concours delictorum and the law of sentencing, offering proposals for the development of a more consistent sentencing regime. The full three-volume treatise will address the entirety of international criminal law, re-stating and re-examining the fundamental principles upon which it rests, the manner it is enacted, and the key issues that are shaping its future. It will be essential reading for practitioners, scholars, and students of international criminal law alike.