This project will develop and experimentally evaluate the effects of a comprehensive smoking prevention program that is an extensive revision of an existing program. The research has four major aims: (1) to compare the effects of the program with a no treatment control condition at the end of one, two, three, and four years of intervention; (2) to experimentally test whether deterrence is increased with a greater number of years of intervention; (3) to determine whether smoking prevention effects are stronger when the program is targeted on middle schools or high schools; and (4) to assess whether having peer leaders conduct the program is more effective than having teachers present it. The presention program focuses on teaching young people skills for dealing with social pressures to smoke. It is more extensive than previous efforts in that the program is presented in grades six through 12 and all students in a given school receive the program. The in-class elements of the program are supplemented by a schoolwide component and by features that increase parental influences to not smoke. A smoking cessation program is also provided at the high school level. The study is designed so that high schools and the junior highs that feed into them are randomly assigned to treatment or control. Twenty such junior high-high school tracks are included in the design, a total of 60 schools. Special attention is given to being able to conduct long-term follow-up.