Not a self-treatment guide--but a detailed, well-based argument for a new way of thinking about back pain. Presently, back pain is considered the result of structural abnormality: injury or factors present from birth cause some dysfunction in the muscles, bones, or supporting tissues of the back, with resulting pain and limitations to movement. Sarno, a specialist in rehabilitation medicine (New York University), would like to abandon the structural theory completely, and many, of his objections are quite convincing. He believes that back pain is caused, instead, by tension--which leads to physical changes in the muscles and nerves of the back, a condition he calls ""tension myositis syndrome."" As he explains it, ""the change is circulatory; tension constricts the blood vessels feeding the involved muscles, and the resultant blood deprivation leads to painful muscle spasm and nerve pain."" Gradually, the tension, pain, and fear of pain interact and increase, until in many people it becomes chronic. Of current treatments--all geared to repairing structural abnormalities--the most successful are heat, massage, and exercise: they cause muscles to relax, allowing greater circulation--and more oxygen to reach the muscle. Sarno attributes relief from other treatments to placebo effects; surgery, he contends, is completely inappropriate. His own model of treatment is based on changing individual responses to tension and stress. (These are not detailed here.) Sarno published his theories in medical journals; this will serve to bring them, deservedly, to a wider, lay and medical audience.