The world's water resources are coming under increasing stress, a stress that will become critical globally sometime during the next century. This is due to the rapidly rising population demanding more and more water and an increasing level of affluence. The book discusses the background to this issue and the measures to be taken over the next 20-30 years to overcome some of the difficulties that can be foreseen, and the means of avoiding others, such as the hazard of floods. It looks at the water resource and its assessment and management in an integrated fashion. It deals with the requirements of agriculture and of rural and urban societies and to a lesser extent with those of industry and power, against the background of the needs of the natural environment. It presents a number of ways and means of improving the management of national and international affairs involving fresh water. It highlights the importance of fresh water as a major issue for the environment and for development.