Though mainly for athletes and outdoor types exposed to the cold, this could also be of real help in caring for the afflicted. Severe winter storms and cold-weather near-drownings have recently highlighted the problems of excessive loss of body heat: basically, all systems slow down dramatically, and eventually come to a halt. The time period before death occurs varies wildly--in some of the publicized cases that the authors comment on, persons were revived after being submerged in icy water for more than 20 minutes. How this is possible, we don't yet know. But Pozos and Born do a nice job of explaining what is known about how the body regulates heat conservation and loss; the causes of hypothermia (prolonged exposure to cold is most common--but fatigue, hunger, and other factors are also important); and the body's reaction to cold--from simple shivering to a deeply unconscious state, with a heart rate as low as one-two beats per minute. The practical advice for athletes (runners, scuba divers, mountaineers) and rescue personnel covers both prevention and treatment. With some extra notes on the elderly (who are especially at risk), concise cold-weather guidance for all involved.