no knowledge of how international offences should be graded according to different levels and degrees of culpability and harm, to mention but a few. Rethinking International Criminal Law: The Substantive Part, brings together a team of researchers and practitioners from the field of international criminal law- concerned with a new international agenda of refining substantive international criminal law. Topics covered are diverse and include the superior orders defence, the mental element, the defence of mistake, command responsibility, the crime of aggression and the principle of legality.