This report examines the Chicago Area Project (CAP), the first community-based delinquency prevention program, from both a historical and a contemporary perspective. The analysis is in three parts. The first part describes CAP's founding in the 1930s and analyzes the process through which it was established and the operation of its prevention programs. The second part examines the operation of the CAP program in South Chicago in 1980, in light of assumptions derived from the historical analysis of the salient features of CAP philosophy and practice. Both parts focus on the ways CAP was implemented and the implications these ways may have had for its success, or lack of success, in preventing delinquency. The third part of the analysis combines census data with data on delinquency rates and data on program participation and operations to develop a rudimentary quantitative method to enlarge upon and with which to make a preliminary validation of earlier analyses. (Author/KH)