Territorial and boundary disputes provide a major part of the work of the International Court. The author considers how cases of this kind come to the Court and the issues of jurisdiction and justiciability they represent; explains how, when the Court decides such cases, it establishes the facts and applies the law; and, finally, discusses the question of implementation and the factors which determine the effectiveness of judgments. He concludes that in territorial and boundary cases, as elsewhere, the Court's decisions serve both to resolve specific disputes and to develop the law, while also highlighting the political context of international adjudication.