No hype or hocus-pocus--but a well-presented case for dietary supplements and a clear plan for determining individual vitamin and mineral needs. As Colgan (Rockefeller University) points out repeatedly, nutritional science is one of the most hotly argued topics in health (eminent scientist A ""rages that vitamin supplements are a waste of time,"" equally eminent scientist B ""claims they are vital""); and no one authority is right. To Colgan, vitamin supplementation is important because our food supply is of poor quality by the time it reaches our tables. (For some foods, he shows the wide variation in nutrients actually round in samples--so we don't know how much vitamin A we actually get from a carrot, for example.) He also believes that significant advances could be made in preventing illness, and improving the quality of life, if we could learn more about optimal (rather than adequate) nutrition. As a practical matter, Colgan explains why each vitamin and mineral is necessary and includes carefully-arranged tables for readers to calculate vitamin and mineral dosages after determining their needs from a questionnaire. (Smokers, among others, have special needs.) Extras include seine timely alerts (at least one of the popular breakfast cereals touted as low in sugar is loaded with salt). Believable advice for those sold on supplements; thought-provoking arguments for skeptics.