This comprehensive, two-volume review of the atmospheric and hydrologic sciences promises to be the definitive reference for both professionals and laypersons for years to come. Volume I addresses atmospheric dynamics, physical meteorology, weather systems, and measurements, while Volume II contains information on the climate system, atmospheric chemistry, hydrology, and societal impacts. Thomas Potter , Professor of Meteorology, University of Utah, Salt Lake City Utah; Director of NOAA Cooperative Institute for Regional Prediction; Weather Coordinator for 2002 Winter Olympics. Bradley R. Coleman (Ph.D. MIT) Seattle, Washington - Science Operation Officer, National Weather Association; NOAA's Administrator Award; Fellow AMS