International criminal law falls within the areas of international law which have progressively developed in the past two decades. This field of law has come a long way since its first steps in Nuremberg and Tokyo after the Second World War and the more recent establishment and functioning of ad hoc tribunals in the Hague and Arusha and the permanent International Criminal Court. In this way, international criminal law has taken confident and decisive steps towards becoming a full-fledged discipline of international law, and towards ridding itself of non-compliance problems so common to the (non-)functioning of general international law. It must be noted, however, that the status of international criminal law as a full-fledged and independent discipline has never been questioned by its practitioners and scholars. In this sense, the Oxford Companion to International Criminal Justice confirms that international criminal law has come of age and become a full standing discipline within international law.