In recent years the science of ecology and the field of conservation biology have progressed rapidly and so we must welcome an up-to-date encyclopedia that covers both these fields. The editors of the volume have brought together over 200 expert authors from 18 different nations. The list of authors is an impressive collection of many of the leaders in contemporary ecology and conservation. They have contributed almost 3,000 entries including 250 longer ones that treat important topics in detail. Other contributions vary from short dictionary definitions to more detailed essays with references and cross-references which greatly facilitate the use of the book. The text is well illustrated with numerous photographs, graphs and diagrams.

The coverage of topics is broad and ranges from basic botany and zoology to theoretical ecology. Particularly strong is the coverage of various types of ecological measurement and this will be of considerable use to students and researchers. For example, there are five pages devoted to Analysis of Variance (ANOVA) including details of one-way, two-way and nested ANOVA. The extensive entry of diversity indices contains a useful table of the characteristics and performance of the major diversity indices, three of which are said to produce misleading results. Four pages are devoted to the Lotka-Volterra model which is of great use for studies on competition, population growth and predator-prey interaction. Most of the statistical methods and commonly used tests and models are clearly described together with references. A few major groups of organisms have their own entries such as angiosperms, bats, beetles, bryophytes, gymnosperms, reptiles and social insects. People are confined to a single page which lists 31 deceased "characters in ecology" from Aristotle to Sewall Wright. Many of these were biologists rather than ecologists, but I am glad to see that the first two directors of Kew, William and Joseph Hooker, both feature. Natural environmental functions, such as atmospheric circulation, upwelling in oceans, the nitrogen cycle and dominance, are included. The most important natural ecosystems, such as boreal forest, prairie, tropical montane and tropical rain forest, rivers and streams, each have entries, but surprisingly savannah merits only two lines. A few countries such as Russia and Argentina have their conservation programmes described, but there is no entry for the United States or the United Kingdom, though a few major regions such as the Arctic and Neotropics have entries.

Many of the basic elements that have important biological rules feature, for example barium, calcium, carbon, lead, nitrogen, tin and titanium, and many elements feature in an extensive treatment of mineral nutrients. There are good entries on research methods and techniques such as cladistics, experimental design, phylogenetic systematics, remote sensing, but no entry for inventory. Many of the causes of environmental degradation are mentioned, such as the effect of motor vehicle pollution, nuclear power, ozone holes, deforestation and dams, among many others. Overall a sensible and balanced approach is taken on these subjects. Some basic biological phenomena - mimicry, pollination, species concepts, succession and plant defence systems - are particularly well described. Five examples of exotic and invasive species are given, including the golden apple snail in Asian rice systems and the brown tree snake in Guam. There are also a few more general items included which all help to make this a most handy reference tool.

There is no entry for DNA, but one for selfish DNA and for DNA banking. The seven pages devoted to sex include items on sex rations, sex-role reversal, sexual conflict, sexual reproductive cycles, sexual selection and a final entry on the "sexy sons" hypothesis in which female choice drives the evolution of exaggerated attractive traits in males, such as the peacock's unwieldy tail feathers. I am also glad to see that the important topic of soil merits seven pages and includes sections on soil classification, soil moisture, soil profile, soil seed banks and soil-vegetation-atmosphere transfer scheme (SVATS) -Jthe path of water from the soil through the plant to the atmosphere.

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I could quibble about some of the omissions. I was sorry to find no entry for botanic gardens at a time when they play such a crucial role in conservation and only six-and-a-half lines for arboreta. I am sure zoological conservationists would have liked to see more than three lines on zoos, too. It is puzzling that Argentina has been singled out for a long and excellent entry on conservation in that country whereas other more biodiverse countries of South America, such as Brazil, Colombia, Venezuela and Ecuador, have no entry. Biophilia, the term newly coined by E. O. Wilson, is in but "biopiracy" is out.

However, the numerous entries that are included make this an extremely useful volume for professional ecologists and students alike. It should be on the desk of any serious conservationist or environmental manager. I am sure that, although I have read through many entries before preparing this review, I will be consulting this book frequently in the future. The cover publicity for the book says that it is for anyone intrigued by the life-dinner principle, the bubble concept, NIMTO or the one-tailed test. You will also be able to find it just as useful for many more familiar terms as well. From aapa mire to the single-celled alga zooxanthellae, this is a useful and fascinating volume.

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Sir Ghillean Prance is director, Royal Botanic Gardens, Kew.