Addiction to tobacco, alcohol, and other drugs inflicts a substantial toll on Americans, measurable in terms of deaths and illnesses, social costs, and economic costs. With approximately 60 million smokers, 14 million dependent on alcohol, and 14 million users of illicit drugs, more than one fourth of Americans over age 15 has a physiological dependence on at least one addictive substance. As a result, nearly 590,000 deaths--about a quarter of all deaths in the United States--are caused by addictive substances: 105,000 from alcohol abuse, 446,000 from tobacco use, and 39,000 from addictive drugs in 1995. The magnitude of addiction's impact on morbidity is also great, causing approximately 40 million illnesses and injuries each year. The economic burden of addiction is estimated at greater than $400 billion every year, including health care costs, lost worker productivity, and crime. Less quantifiable, but equally important, are the social costs to families and communities of addiction. Children of substance-abusing parents are more likely as adults to become plagued by addiction and its related problems. Passive exposure to tobacco smoke affects nonsmokers; drug and alcohol abuse are risk factors for crime and incarceration, family violence, fatal and permanently disabling accidents, birth defects, and divorce. Combined, the effects of tobacco, alcohol, and drugs inflict a greater toll on the health and well-being of Americans than any other single preventable factor.