This collaboration between an American and an English scientist, friends and colleagues for a score of years, is a fascinating idiosyncratic study of ""Man the Peculiar Animal,"" to use the title one of the authors chose for an earlier Penguin book. It is fascinating because the authors convey their own fascination so enthusiastically. And idiosyncratic because they choose only those phases of man's anatomy or physiology which point up man's uniqueness. So you will not read about respiration and digestion here, except as they relate to man's posture. You will read about his skin (man is the only creature to have acne), his teeth (their order of development is unique), his reproductive system and the cycles of pregnancy and menopause (many uniquenesses here). There are fine summaries of the hormonal systems, sensory modalities, brain, skeletal development, locomotion, and speech--always with lucid descriptions of the mechanics or chemistry involved, and always compared and contrasted with other primates and lower mammals. Lest there be any smugness about man's position at the top of the evolutionary heap, the authors close with some sober thoughts on aging (though including a fine irrelevant table of longevity by profession which shows that U.S. cabinet officers live longest), and a summary of the weaknesses the flesh is heir to as a result of man's achievement of the state of large-headed bipedal naked-apeism.