Water is basic to terrestrial life, and its distribution has controlled the growth and spread of human civilization. The importance of water to modern industrial processes, urban planning, and agricultural development is hard to overestimate. With these compelling motivations, it is natural that more tech nical and scientific study should have been devoted to this one substance than to any other. Research on water and its solutions has exhibited a marked expansion during the last decade. In sig nificant degree, this has resulted from the availability of new experimental tools and techniques, and of dramatic advances in computing science. This combination, in skilled hands, promises eventually to explain the unusual properties of water and aqueous solutions in unequivocal molecular terms. like wise, one now has reasonable hope that the active role that water plays in biochemical processes will be revealed and explained quantitatively at the molecular level. Owing to the widespread scholarly interest in aqueous science, it is clear that guides to the overwhelm ing literature on the subject are valuable. They serve ideally to indicate what is known and what is not, which areas harbor controversies, and what types of research attacks seem most fruitful (in answering more questions than they raise!). Whatever time and resources need to be spent in preparing compre hensive bibliographies should be quickly offset in the total scientific community by the efficiencies generated.