) This proposal describes a plan for a Preventive Oncology Academic Award and my personal development towards a career in the design and implementation of behavioral interventions for cancer prevention and control. Two research projects are proposed. The primary conceptual framework for both the studies is Prochaska and DiClemente's Transtheoretical Model of Behavioral Change, which has been widely used for assessing adult smoking, but not adolescent smoking. The first study is a behavioral determinants study of adolescent smoking maintenance and cessation. Using a cross sectional study design, 1530 high school students in Houston, Texas will be surveyed and their current smoking status will be assessed. The distribution of adolescent smokers across stages of change in their intentions or efforts to quit smoking will be determined and the psychosocial and sociocultural factors that are related to each stage will be assessed. The second study is an intervention study to pilot test strategies that facilitate smoking cessation among an adolescent population. Focus groups will be conducted to assess receptivity to a variety of intervention strategies and messages. Based on the results of the behavioral determinants study and these focus groups, intervention strategies will be developed. Three hundred and six current and former smokers from four Houston high schools will be recruited and assigned to intervention and comparison conditions and followed for six months in order to determine the effects of the intervention and the movement through the stages of change over time. The specific intervention messages and strategies that students in the intervention condition will receive will be determined following Study 1, but will include individually tailored messages, the use of peer role models, and small media. These two research projects offer a unique attempt to reduce tobacco use through a planned approach to behavioral intervention, and should lead to the further development and implementation of a large scale intervention strategy to reduce smoking the 20 to 30 percent of young people who have started smoking and may be addicted to nicotine.