The fourth edition of the World Water Development Report (WWDR4), ‘Managing Water under Uncertainty and Risk’ is a comprehensive review of the world's freshwater resources and seeks to demonstrate, among other messages, that water underpins all aspects of development, and that a coordinated approach to managing and allocating water is critical. The Report underlines that in order to meet multiple goals water needs to be an intrinsic element in decision-making across the whole development spectrum. It was launched at the 6th World Water Forum in Marseille by Irina Bokova, UNESCO Director General, and Michel Jarraud, UN-Water Chair.