In the broader context of the accountability of international organisations, this book focuses on the obligation of the United Nations - like many other organisations - to ‘make provisions for appropriate modes of settlement of [...] disputes of a private law character’ to which it is a party. The book advocates a systematic approach in conformity with the rule of law in discharging that obligation. That is needed to increase the legitimacy of international organisations, while bolstering their jurisdictional immunity. The work also develops the basic features of a comprehensive dispute settlement mechanism, complemented by a new United Nations convention.