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The Science of Allelopathy . Edited by A. R. Putnam and C-S. Tang. New York etc.: Wiley (1986), pp. 317, £50.40.

This book on allelopathy is well produced but expensive. It is written by some twenty leading authorities, mostly American. The book, following an introductory chapter by the editors, is divided, like Gaul, into three parts: (1) field observations of allelopathy and autotoxicity; (2) techniques for studies of allelo-chemicals and their modes of action; and (3) chemistry and potential uses of allelopathy. In general, the book is both assertive and yet defensive, for the subject (the chemical interactions between plants) is not without its critics, who question whether it has any significance, or even if it occurs at all. The book's title, 'The Science of Allelopathy', suggests a concept crowned with respectability and yet, while many examples are quoted as fact throughout the book, the editors admit that investigators have seldom achieved convincing proof. The usefulness of the work lies in its up-todate review of a burgeoning subject and in the later parts, which indicate something of the techniques and chemical requirements of the subject. But where does all this enthusiasm lead? Undoubtedly, the search is on for novel growth regulators or herbicides, which could prove the ultimate in plant regulation by man. R. J. Chancellor