This book explores the record of the UN development system (UNDS) over more than 70 years as a fount of ideas and concepts in development; as a contributor to development thinking and strategy; and as the principal source of global development goals from the first UN Development Decade to the SDGs. It also examines the more mixed record of the UNDS in its operational role and asks how the ideational and operational functions can be more successfully aligned, and what changes such an alignment would imply. The chapters consider: The logic of global governance through international organizations The origins, functions, structure of the UN development system UN contributions to development thinking The UN’s development agendas, 1960s to 2015 Reforming the UN development system The future of the UN and multilateralism The book will be of great use for students and scholars studying political science, international organizations, the UN, and development, as well as for practitioners associated with the UN, including member-state missions, UN staff, and development cooperation professionals.