Arid regions today face more difficult problems than ever before. The world's sand deserts appear to be enlarging, and droughts are contributing to the economic devastation of whole nations. The six drought-stricken Sahelian nations provide an extreme illustration, but industrialized and developing countries both suffer from the crisis. The southwestern United States, for example, faces falling water tables and increasing groundwater salinity. Nevertheless, arid lands have underexploited agricultural potential. We should learn that this potential can be best developed by concepts and methods specifically suited to dry regions. Water practices developed for temperate climates may not work as well in arid regions for technological, environmental, economic, and cultural reasons. We need fresh, innovative approaches to water technologies, particularly those designed to meet the needs of arid regions in the less developed world, where there has often been improper application of practices developed in regions with higher rainfall or more abundant water supplies. Also, we need to reconsider practices developed in arid regions by ancient agriculturalists. Basically there are two approaches: increasing the supply of usable water and reducing the demand for water. Supply and demand, as well as delivery, have to be considered for an integral system. Little-known but promising technologies for the use and conservation of scarce water supplies in arid areas are the subject of this report. Not a technical handbook, it aims to draw the attention of agricultural and community officials and researchers to opportunities for development projects with probably high social value.