Low back pain is a puzzling, multi-faceted condition, and this guide for dealing with it gives chronic cases some hope. Lettvin concentrates on the importance of patterns (observing when pain occurs, learning what movements provide relief) and the conditions that exacerbate the problem (scoliosis, pregnancy or obesity, constipation, stress). A TV exercise instructor and MIT lecturer, she insists first of all on a doctor's examination and diagnosis, and discusses the options medicines like Valium can provide. But her emphasis is on learning to live with--and preferably without--the pain by cultivating habitual movements that strengthen the durable stomach muscles and ease up on the fragile back muscles. She recommends using pillows to offset postural irregularities while sitting or reclining, encourages assumption of a kind of foetal position to comfort irritations, and suggests standing-walking-carrying in prescribed ways. What makes this Maggie's book are the exercises specified with particular weaknesses in mind, always with the warning to stop at any sign of pain. Sound advice supported by standard therapeutic practices.