The 236 entries in this book comprise an A-Z overview of water's manifold roles in human society and the natural world throughout history. Scientific and technical issues are explored, including the physical and chemical properties of water, steam, and ice; the uses to which water and steam are put; and the purification, transfer, and uses of water by communities. The hydrologic cycle is explained, with attention to the properties and distribution of ice masses, and the properties of oceans and rivers.