Somnambulism, insomnia, dreaming, even bedwetting (2% of the adult population): nocturnal intrigues according to modern research and theory. References to blood pressure changes and latent dream content, EEG's and REM's (Rapid Eye Movements) presume a wide-awake reader; fortunately, style and subject are natural stimulants. As discussed also in Kettelkamp's Dreams (p. 277. J-105), studies of dream (REM sleep) deprivation point to a compensatory daytime increase in ""basic instinctive drives."" Physiological mechanisms--hormones, biological clocks, Olds' pleasure center--are also considered, even a few ho-ho superstitions about ho-hum routines: e.g. Dickens' refusing to sleep unless his bed pointed north. Most researchers agree that modern generations need less sleep than their ancestors, especially in communities offering a larger number of activities, and city people survive on less sleep than, say, Eskimos. This won't get kids to bed early or put them to sleep--strong light on a relatively unexplored area.