To be a neurologist these days you have to know the traditional fields of anatomy, physiology, medicine and surgery, but to do research it also pays to know psychology, psychiatry, ethology and biochemistry. In particular these last two fields seem to be having a marked fertilizing influence and Nathan's book is a fine example of this effect. Nearly every page describes some interesting bit of animal behavior, whether it's how dolphins sleep (with one eye open and coming up for air twice a minute) or why dogs assume their familiar posture when urinating (it's a secondary sexual characteristic dependent on hormones). This sort of material is endlessly interesting even if it doesn't always serve to illuminate the workings of the nervous system--sometimes it's just one puzzle illustrating another. Nathan, who is a research neurologist at London's National Hospital, covers all phases of the nervous system and behavior in this volume, from the chemistry of the nerve impulse to the topography of the brain. Such a survey always reveals some bias on the part of the reader and the writer. So for example one would have liked a bit more on the physiology of perception and a bit less on the more vague generalizations about parasensory and association areas. Especially good, however, is his treatment of the hypothalamus and related forebrain structures in mediating emotional behavior and organizing many of the vital functions of life.