This book deserves wide attention, which may be enhanced by a tie-in with an ecological exhibition at Chicago's Field Museum. Ruth Moore, well known for The Earth We Live On (1956) and other works of popular science, patiently and skillfully outlines the major ecological issues confronting the next decades. In half a dozen short chapters she manages to synthesize a remarkable amount of fact and opinion about ecosystems, food chains, the chemistry of life, population densities, atmospheric pollution and photosynthesis, the impact of technology. Her repeated message is very simple: the ecological diversity toward which nature tends (when not fooled around with) is inevitably more stable than the simplified systems which man has introduced in the name of productivity. (Even prehistoric man--who turned vast forested areas of Asia and Africa into desert.) She explains that a population of many plant, animal, and insect species brings a set of inherent checks and balances to its neighborhood; the same neighborhood exclusively devoted to wheat invites unchecked growth of one species of bug. Much of this material is by now familiar, but Ms. Moore handles it with masterly grace and confidence. She sums up various perspectives on the future of our beleaguered planet--from the Club of Rome's review of mutually limiting options to Heilbroner's sanguine expectation of exponential growth in technology as well as population--but makes no bones about her own conviction that the tiniest interference with the earth's chemistry may mean the beginning of the end of its ability to support life. An object lesson in how to handle a scientific can of worms.