<qa>  What is the most preventable cause of mortality?Smoking is the greatest preventable cause of mortality and a significant economic burden. Even with the best available treatments, most smokers relapse within days or weeks after a quit attempt. Nicotine replacement therapy, the most widely used pharmacotherapy, yields end of treatment quit rates of 25 suggesting that managing nicotine withdrawal is not sufficient. To improve quit rates significantly, a more refined mechanistic understanding is needed. Neuroimaging can identify mechanisms underlying behavior change beyond self-report and behavioral measures. Functional magnetic resonance imaging fMRI studies show that brief e.g., 24 hr. abstinence from smoking produces working memory deficits associated with reduced neural activity in cognitive control circuits and weakened resting state functional connectivity. Neural reactivity to smoking cues also increases risk of relapse, and psychological stress can enhance neural responses to smoking cues and increase smoking intensity. This study will examine how abstinence-induced brain changes contribute to clinical outcomes in treatment-seeking smokers. Using a validated fMRI abstinence challenge paradigm, 200 treatment-seeking smokers will complete two 1-hour pre-treatment fMRI scans: after smoking satiety and after 24 hours of confirmed abstinence. The investigators will examine brain responses during performance of tasks probing working memory, cue reactivity, and stress response as well as resting state functional connectivity. Participants will then set a target quit date, receive smoking cessation counseling, and be monitored for 6 months to assess time to relapse using a validated smoking relapse protocol. 