From scented soap to incense to perfume to ""scratch-and-sniff"" ads to sex-related pheromones (hormonal secretions), human beings are truly led about by their nose. Not as much as dogs maybe (who have 44-times the number of olfactory sensors as we do) and whom British scientists have suggested using to make medical diagnoses (schizophrenics might well go crazy; they really do smell), but enough to make us spend half a billion a year making products from deodorants to greeting cards to jaguars smell pleasant. Lest we feel bad, the author assures us that it's nothing new: Napoleon used several bottles a day. Of course, a draftee might think underarm odor is not so bad if it gets him out of the army--as it does in Japan. This is an engrossing oddball of a book, carefully assembled, brightly written, full of theories and tidbits about our most neglected (and under-appreciated) sense.