With the overall incidence of lung cancer increasing and little progress being made in effective treatment, new approaches to this disease, such as early detection and prevention, are desperately needed. Rapid advances in molecular oncology over the past decade have provided us with new insights into the pathogenesis of lung cancer. Characterization of molecular changes in growth-regulating genes in lung cancer cells has been a first step toward identification of molecular markers of early lung cancer. In addition, we have made great strides in our understanding of the process of tumor promotion in lung cancer by the identification of specific substances as tumor promoters and the biochemical pathways by which they function. These insights will provide us with a beginning for the development of screening assays, early detection tests, and chemopreventive agents, hopefully allowing us to make an impact on lung cancer mortality.