The author of The War Magician (1982), A Race on the Edge of Time (1987), and seven novels (including, as coauthor, Hostage One, 1989) takes on the earth's greatest ecological threats in this lively, up-to-the-minute treatise, and suggests practical ways to head them off. In the Seventies, headlines resounded with scientists' predictions of a new Ice Age. In the Eighties, ozone depletion, the greenhouse effect, and the possibility of nuclear winter took over the spotlight. Fisher's aim here is to summarize, in easily digestible paragraphs, the known ecological damage so far, and to emphasize that the earth's climate is determined by so many delicately balanced variables that it would take more computer time to accurately predict our planet's fate than we have left to avoid the danger. He corrects misconceptions caused by conflicting newspaper articles by pointing out that scientific estimates of the extent of the damage can and do change, and reminds readers that a mere five-degree change in mean temperature would put most of the northern hemisphere's major urban centers under either seawater or glacial ice. His solutions for these woes include the advancement of nuclear energy, immediate action to help develop alternative power sources for developing countries, international cooperation on manufacturing restrictions, and steady nuclear disarmament. He also urges both an awakening of individual conscience in everyday activities (energy conservation, self-education on the issues) and renewed political activism. Appending a list of organizations dedicated to solving these dilemmas, Fisher manages to end on a positive note, even in the face of such monumental dangers. A powerful and hopeful book that goes far to clear up confusion and that should find a secure place among a concerned readership.