This all-purpose nutrition guide is undoubtedly authoritative: Gershoff is dean of the top-rated Tufts Univ. School of Nutrition and editor of its newsletter. The book is also broad and practical in coverage, with chapters on separate nutrients followed by simple advice on grocery shopping, reading labels, eating out, and nutrition at different life stages, then a 21-day low-cholesterol diet, and cancer and other concerns, and pointers on weight control and fitness. The approach seems cautious to the point of political timidity, however. Gershoff maintains that there is no nutrition establishment and no controversy among scientists. Does he forget how long it took for the medical establishment to acknowledge the cholesterol connection? He goes very easy on industry and government agencies, which are always ""engaged in efforts to improve"" such problems as the widespread presence of salmonella in chicken. He overplays FDA vigilance and downplays problems with pesticides and contamination; and he gives additives ""as a category"" a green light, noting that some are foams of nutrients, without mentioning the controversial ones such as dyes. None of this disqualifies the guide: It's the sort of handbook all libraries will want, and should have. But it's disappointingly conservative at a time when The New York Times is running front-page features on food-safety problems.