The authors review developments in understanding smoking cessation interventions over the past decade. Noteworthy is the unprecedented growth of research and knowledge that has left a deeper understanding of how best to use new and existing behavioral and pharmacologic tools and strategies to help smokers quit. The status of public-health-level interventions is evaluated, questions are raised concerning their efficacy, and suggestions are offered for further refinement of these intervention strategies. Development of cessation guidelines is reviewed, and the state of knowledge concerning behavioral and pharmacologic interventions is summarized. The authors also present agendas for behavioral and pharmacologic research related to smoking cessation and discuss individual difference factors among smokers that may prove to be important in designing new and refining existing treatments.