Mr. Meyer, whose presentation of such subjects in science as paper, engines, prisms and lenses is very well known, now produces a tankful of information on water that should prove to be helpful and is fairly definitive for this age group. The book discusses the chemistry and physical properties of water, its purification, its harnessing for power, sanitation and irrigation. The last section is concerned with water conservation (problems and methods) and stops at the up-to-the-minute report of projects involving the desalinization of sea water. The photographs and the diagrams by John Polgreen are clear and their labelling, as well as their placement, back a smoothly written text. The index is short but complete. Well done and a boon to science book reports.