This article examines data from 10 longterm prospective studies (N greater than 5,000) in relation to key issues about the self-quitting of smoking, especially those discussed by Schachter. When a single attempt to quit was evaluated, self-quitters' success rates were no better than those reported for formal treatment programs. Light smokers (20 or less cigarettes per day) were 2.2 times more likely to quit than heavy smokers. The cyclical nature of quitting was also examined. There was a moderate rate (mdn = 2.7%) of long-term quitting initiated after the early months (expected quitting window) of these studies, but also a high rate (mdn = 24%) of relapsing for persons abstinent for six months. The number of previous unsuccessful quit attempts was unrelated to success in quitting. Finally, there were few occasional smokers (slips) among successful long-term quitters. We argue that quitting smoking is a dynamic process, not a discrete event.