Tobacco use behaviors in the U.S. have changed significantly over the past century. After a steep increase in cigarette use rates over the first half of the 20th century, adult smoking prevalence rates started declining from their peak reached in 1964. Improved understanding of the health risks of smoking has been aided by the U.S. Surgeon General's Reports, issued on a nearly annual basis starting in 1964. Among the many forces driving down smoking prevalence were the recognition of tobacco use as an addiction and cause of cancer, along with concerns about the ill effects of breathing secondhand smoke. These factors contributed to the declining social acceptance of smoking, especially with the advent of legal restrictions on smoking in public spaces, mass media counter-marketing campaigns, and higher taxes on cigarettes. This article reviews some of the forces that have helped change the public image of smoking, focusing on the 50 years since the 1964 Surgeon General's Report on smoking and health.