The Hindu Kush-Himalayas (HKH) are the largest storehouse of fresh water in the lower latitudes and as such are important water towers for nearly 500 million people. They are the source of major river systems: the Indus, the Ganges, the Yarlung-Tsangpo, the Brahmaputra, the Nu-Salween, the Yangtze, and the Mekong. Also called the Third Pole they contain the largest mass of ice and snow outside the earth's polar regions. Located at the highest elevations on earth, with the permanent snowline at about 5,000 m, the mountain peaks of the HKH extend close to 9,000 m. These peaks contain many glaciers, including some of the longest outside the polar regions. Availability of water at such great heights has also made human life possible at higher elevations than elsewhere, with human settlements beyond even 4,000 m and temporary and seasonal settlements with unique cultures and traditions even close to 6,000 m. The extreme variability of climate and precipitation patterns, as well as extremely inadequate knowledge on the hydrology of the HKH rivers and streams and the complex interrelationships between ecology and hydrology in the region, impose serious scientific and technical limitations on the development of HKH waters. Limitations make it difficult to improve the knowledge base that is essential for dealing with existing uncertainties associated with variability in climates and precipitation. In addition, unknown factors concerning the impacts of global warming and climate change complicate the problem. This two-volume document discusses the methods of harvesting water throughout the HKH mountains amongst a wide variety of human groups.