The Max Planck Yearbook of United Nations Law (UNYB), founded in 1997, appears under the auspices of the Max Planck Foundation for International Peace and the Rule of Law. Volume 25 of the UNYB is a special anniversary edition that features contributions which look back on the key developments in the United Nations’ activities in the field of international law since 1997. By concentrating on issues connected with the UN and its initiatives, the UNYB aims to facilitate an understanding of the changes the UN has been undergoing since its foundation. It also provides a forum in which the potential of international organisations to affect the future course of international law and relations can be examined and assessed. Articles featured in the UNYB either relate to ‘The Law and Practice of the United Nations’ or ‘Legal Issues Related to the Goals of the United Nations’. The UNYB addresses both scholars and practitioners, giving them insights into the workings, challenges and evolution of the UN.