The book reads like a long magazine article -- in fact it may well be too brief. The history of sanitation and water purification is glanced over -- no dates, no names, few reasons, few results. Or, take the case of water pollution. This is a hotly contested issue in some states, and with commercial implications everywhere, yet none of the legislative measures, none of the documented disasters (dead fish, disease, etc.) are quoted. There is a little about the possibility of electricity from tidal power, but not much about how. There is a little about the de-salinization of sea water, but not much about the equipment or the costs. The widespread pollution of water by detergents is mentioned as something that is being solved by purification plants, but there is no mention of steps taken in other countries restricting the manufacturers. Irrigation systems and dams as consumers and controllers of water are too briefly covered to provide more than a nodding acquaintance with the presence of a continuing problem. The author is an experienced science/technical writer and editor. His book reflects his journalistic competence: well organized and clear, but too short to do more than hit the highspots.