This publication, by Philippe Couvreur, Registrar of the International Court of Justice since 2000, offers an account of the history and main achievements of the principal judicial organ of the United Nations, the only court with universal and general jurisdiction. The book discusses the hopes and aims of creating a permanent, international tribunal for settling disputes between States, and the ICJ’s role in ensuring the effectiveness of the rule of law at the international level. Taking into account the characteristics of the international legal order, this work provides a description of the main achievements brought about in this respect by the creation of the ICJ; the basis and scope of its function as a judicial institution; its relationship with other means of settling disputes and its integration in the United Nations; and finally its substantial contribution in two areas of great significance for the promotion and strengthening of peaceful relations between States, namely the settlement of land and maritime disputes and the implementation of the law of State responsibility.