The design of the study comprised two conditions: 1) Control Condition (N = 452) and 2) Enhanced Treatment Condition (N = 452). the two treatment conditions had a common core seven-week cessation and relapse prevention group program. Following the group program, the two conditions differed in both format and content of treatment. Subjects in the Control Condition received seven counselor-initiated phone calls over a three month period. The content of the phone calls represented the most effective components of the study and varied depending on whether the subjects were smoking or abstinent. Treatment in the Enhanced Condition was tailored to three groups of subjects: smokers, abstainers, and relapsers. Subjects who were smoking at the end of the core program received three more weekly group meetings followed by three phone calls, and then six monthly calls. The content of their treatment was based on the factors that the study found most related to failure to quit (negative affect, low motivation, low efficacy). Subjects who were abstinent at the end of the core program received seven phone cells over a three month period and then six monthly calls. The content of their treatment included efficacy and motivation building exercises as well as the continued contact for six more months than in the Control condition. Follow-up data were collected every three months for 15 months beyond the core cessation program. The hypothesis was that the Enhanced Treatment, compared with the Control, would improve rates of recycling after a failure to quit, decrease relapse rates, and increase sustained recycling following a relapse.