This collection of papers represents the outcomes of the International Symposium held in Delft, The Netherlands, on June 13-15, 2007, at the occasion of the 50th anniversary of the UNESCO-IHE Institute for Water Education. The papers discuss how to contribute to the sustainability of effective international development and water management with a digest of lessons learned on local knowledge and capacity development. Authors expose recent research, strategies and policy positions. Water for a Changing World starts with an introduction and overview of the water resources and the water supply and sanitation sectors in developing countries and worldwide. Topics of these reviews are water security, environmental integrity, the newest earth system science technologies, integrated urban water management, and the global-local nexus of water governance. The second part presents positions on catalyzing and disseminating knowledge and capacity development in response to the current challenges and opportunities. It consists of a variety of papers on theory and analysis of capacity development, methods and case studies, and policy positions. The authors represent a diverse and representative group of prominent actors, practitioners and academics within the water, sanitation and development sectors.