Introduction to special section: clinical research in smoking cessation.

Although tobacco smoking is becoming less common in the United States, it remains perhaps the most important behavioral problem treated by psychologists. Research interest in smoking has greatly increased among psychologists, but success rates of formal treatment programs for smoking cessation have remained stubbornly low. This article introduces a series of 9 reviews that examine the current status of several diverse areas of research in smoking cessation and provide directions for future efforts in these areas in an effort to promote more innovative investigations.