Book Reviews theory of the problems and the restoration technique, a description of application procedures and case stndies, the discussion of costs and potential negative impacts, and an extensive bibliography. The control of non-point sources of nutrients and the introduction of pure oxygen into the hypolimnion have, however, not been considered. On the other hand, the P-precipitation is overrepresented (not less than 3 figures dealing with rt-lationships of Beanmi? degrees and Al dosing with gallons, Fahrenheit and pounds as further units). I n the "pictorial summary of the eutrophication process" on page 22, the same moment is givm to t,he "income of organic matter and silt" as it primary cause of eutrophication as to "nutrient loading and concentration". This equalization in significance is not justified, because even in wast,e trent>ment lagoons t,he phytoplankton growth and the oxygen balance much more depend on the nutrient loading than on t,he organic loading. It is also questionable whether macrophytes, in the context of eut.rophicat,ion, nearly exclusively may be considered as "subsides of nntrients and energy to the open water".
With respect to the practical application of in-lake control techniques, this book offers coniprehensire information and may serve a s a nseful guide to ii broad resdership.
D. UHLKUN