It's been nearly 45 years since Grand Rapids, MI, approved this country's first citywide fluoridation program. In that time the steady growth of evidence drawn from surveys and other research has yielded inarguable conclusions on fluoride's benefits to oral health. Today, it is one of the country's most heralded public health measures. By 1988, 41 of the 50 largest cities in the United States were served by fluoridated water systems. Yet in some communities the measure still draws fire. Antifluoridationists have charged, among other arguments, that fluoridation proponents are part of a Communist plot, aimed at poisoning the American people and taking over the government. Looking back over the past four decades, fluoride has had a role in a variety of arenas in American life: political, social, medical, and economic. This month's Emphasis takes a look at fluoride's heritage, and considers some of the most recent findings on its safety, benefits, and cost-effectiveness.