The multifaceted nature of smoking includes its physiologic, social, and psychologic dimensions and its career features. It develops over time, through phases such as experimentation or conditioning. It also is given up over time, often after several unsuccessful attempts. Several repetitions of a sequence of considering cessation, attempting to quit, and relapsing are likely to precede permanent cessation. Those who are not ready to commit themselves to quitting may be reached by low-key information more than by too forceful exhortation. Those who are ready to quit may select from among a range of approaches, including group clinics, "self-help" manuals, and physician counseling. Maintenance requires as much attention as does cessation. Cooperation from those around the quitter, reminders to use skills for coping with stressors or temptations, and continued encouragement from the physician may all encourage long-term abstinence. Owing to the multifaceted nature of smoking and quitting and the multiple approaches to cessation and its maintenance, the physician may best be viewed as a catalyst for nonsmoking. If appropriate to his or her practice, this may include extended patient counseling, but those unable to provide this may still make great contributions through brief information on why it is important to quit, encouragement to do so, timely referral to other staff or to materials and programs available in the community, and continued expression of interest in the patient's efforts and/or success. All these may catalyze quitting without demanding excessive time or skills beyond those commonly employed by the physician. In catalyzing nonsmoking, the physician can also be an effective proponent of community or voluntary agency programs as well as institutional and governmental policies to limit smoking in health care facilities and public places. The American College of Chest Physicians' policy encouraging nonsmoking among its Fellows and in their offices is an excellent example of this catalyst role.