This technical guide to hydrological practice, produced by Unesco, is an unusually complete and well-written compilation of basic techniques in both field measurements and their interpretation. It should prove to be a most useful book, especially in the less-developed countries, for technician training, as an introductory text, or as a reference.

The Editors, V. A. Ouryvaev of the USSR State Hydrological Institute, and C. Toebes of the New Zealand Ministry of Works Soil and Water Division, have produced a truly international and comprehensive work, with the aid of 50 contributors. Their text is clear and easily understood, even by one not versed in hydrology.