Efforts to understand trends in and patterns of lung cancer are well served by studies of trends in and patterns of tobacco use. In the United States, the manufactured cigarette emerged as the tobacco product of choice shortly after the turn of the twentieth century. Lung cancer emerged after years of inhalation of cigarette smoke, first among men and then among women. The massive public health education campaign that began after scientists recognized the dangers of cigarette smoking has contributed to large reductions in cigarette use and subsequent smoking-attributable morbidity and mortality. Since 1965, the prevalence of cigarette smoking among US adults has declined by almost half, with positive trends observed among persons in almost all sociodemographic groups and efforts to reduce disparities recognized as an important goal in public health. An epidemiologic approach to understanding and controlling patterns of tobacco use is proposed. The model focuses on the agent (tobacco products), host (consumer or potential consumer), vector (tobacco companies and other users), and environment (with influences from families, social sources, culture, history, politics, law, and media). Accelerating progress in reducing tobacco use will accelerate reductions in tobacco-attributable morbidity and mortality.