Hundreds of millions of people in the world today are starving in the sense that they are chronically hungry and have no chance of leading the normal life which is widely regarded as a human right. The global crisis of food supply which faces us has been brought about by a combination of several factors. The excessively slow rise in the production of food for a steadily growing world population has been accentuated by a number of temporary setbacks. The importance of water is also underscored by the fact that the thirty-eight poorest countries in the world are all situated in areas bordering regions of either snow or desert. The quantities of water used by man for water supply and irrigation are quite small in relation to the total magnitude of water resources, but developments are moving fast, and the percentage of total water resources required for the maintenance of human society is rising steeply.