Hardin Jones is Professor of Medical Physics and Physiology at UC, Berkeley, where for several years he has given a popular course in drug abuse. This volume, edited by his wife, is a distillation of the course with additional material based on interviews with 1,900 addicts, travel to drug-rich parts of the world, and a survey of rehabilitation centers. By the author's definition, ""sensual"" drugs are ""those that the body has no need for, but that give the user a strong sense of pleasure."" His position is that the more the individual is educated about the physiological effects of drugs, the less likely he or she will risk taking them. Recognizing the strong association between drugs and sexual pleasure, he points out that many drugs first titillate erotic sensations but eventually numb feelings. Indeed the drug abuser ultimately becomes sensually deprived--in all senses. Heroin, cocaine, marijuana, alcohol, LSD, and amphetamines are different in their effects, of course, and Hardin reviews current medical lore for each separately. In general, continued use of a sensual drug upsets hormone or enzyme balances at best and destroys tissue at worst. Hardin's approach to withdrawal and rehabilitation is equally no-nonsense: the addict must be motivated. One way is to convince him that full sexual potency and pleasures as well as other bodily delights can be restored. Hardin advocates programs aimed at rendering the addict drug-free and operating at a better level on all fronts. HIS last chapter is a strong admonition against liberalizing marijuana use; along with other authorities, he feels that the drug's effects are insidious and long-lasting. A sane and sensible book, full of information and free of preaching.