Water is one of the basic necessities of life—no organism can survive in its absence. In recent years, however, it has become increasingly clear that our public water supply is not as pure as it should be, and many are questioning its high chemical content. Beaches, seas, and oceans themselves are being increasingly contaminated. Plankton are beginning to die and the Earth is being deprived of one of its primary sources of oxygen. In this important addition to the Nature"s Gift series, Jan de Vries discusses the implications of this self-inflicted damage and points out the health risks of the various forms of water contamination.