We are assured that heart surgeon Barnard played a major role in outlining and reviewing this compendium of body lore, health talk, and tips. Indeed, there is a fat section on the heart and circulation with perhaps a mild in-house joke: ""A desk-bound editor's weak, flabby heart,"" we are told, ""may have to work twice as hard as a long-distance athlete's to run the same distance in the same time."" That's a typical example of the pithy prose that runs through this no-nonsense text-and-picture book--a remake of those perennial favorites, the home health guides, which unabashedly espouses a mechanistic model: i.e., your body is a machine, with pumps, pipes, gears, and gaskets, served by master switches and a complex computer. For those who delight in facts, there are descriptions of major body parts and functions, duly laced with statistics (there are 206 bones in the body; your skin weighs twice as much as your brain; you have 3 million sweat glands, etc.). The style is clean exposition of the Time-Life variety; and this too is a large-format, heavily illustrated volume. You will get to look at (as well as read about) body parts, private and otherwise. One cannot fault the generally clear descriptions of physiology and development, diseases and disorders, care and treatments. But be wary of the popular psychology and sociology. ""Evidence also points to a correlation between adrenaline/noradrenaline ratios and social class. It seems that a person who is lower down the social order is more likely to have high base levels of noradrenaline."" (Noradrenaline is a hormone associated with aggression and violence.) The thinking expressed on premenstrual tension, homosexuality, criminality, and such is not likely to win liberal support either. Body mechanics are something else: Barnard et al. say a lot, and say it well--with pictures.