) Among African Americans both the incidence and mortality from all cancers combined are increased relative to the majority population. Randomized clinical trials represent a crucial means to obtain new information about preventive therapeutic innovations. In general, however, African Americans have been under-represented in this research, despite a growing awareness of the need to recruit participants from broad strata of the population. Factors which determine the low minority participation in clinical trials are complex and it is likely that solutions will be achieved in an empirical fashion. Small scale, pilot studies should be particularly well suited to this purpose. The most obvious potential benefit from these studies would be an efficient method of identifying motivate individuals who might be eligible for enrollment in community-based screening and prevention reseach. A variety of general approaches to recruitment for such studies exist, including mass media publicity, use of pre-existing social organizations (work sites, churches, etc), or canvassing (door-to-door, telephone). In this application we propose to test a novel approach to recruitment which will make use of naturally occurring social networks. In Maywood, IL., a predominantly African-American suburb of Chicago (pop. 27,000), we will use the high school as a means of accessing households. Adult members of the household will then be asked to identify other individuals in social networks (eg, extended family, friends) and formal organizations to which they belong (churches, unions). These individuals will be invited to participate in a flexibly designed cancer screening and education program. The yield for this process of recritment will be measured, costs in staff time quantified and compared to yields obtained from an ongoing diet intervention trial in the same community. The design of this project is based on the hypothesis that social networks will provide a generalizable method to identify clusters of motivated individuals who would be willing to participate in cancer prevention trials. We will test whether accessing these networks will provide participant yields at least as good as those experienced with both the Women's Health Initative and a door-to-door recruitment protocol. If these procedures prove successful, the opportunity exists to establish a method which can be used in a much wider context.