Sperling (sanitary and environmental engineering, Federal U. of Minas Gerais, Brazil) has broken up the material in his Biological Wastewater Treatment in Warm Climate Regions into six smaller books that can be purchased and used more easily. Here he covers all major process technologies and variants of activated sludge and aerobic biofilm reactors, including main concepts, working principles, expected removal efficiencies, design criteria, design examples, construction aspects, and operational guidelines. The books can be uses as texts at academic institutions and as references for practicing engineers and scientists. IWA in Britain now published many reports formerly published by AWWA Research Foundation (Denver). Distributed in the US by BookMasters. Annotation ©2007 Book News, Inc., Portland, OR (booknews.com)