There are enough juvenile delinquents in Los Angeles County to justify a broad prevention effort. Delinquency prevention is strongly cost effective compared to the costs of responding to delinquency after it occurs. Prevention services for the network cost, on the average, less than $250 per case. The average juvenile arrest in the county represents about $1,754 in law enforcement and justice system costs. If the network is to be successful, it must service clients with a potential for delinquency. About 46 percent of the network's clients had an arrest record, and as many as 58 percent may have had some official police contact. Other data indicate a relatively high level of delinquency risk among network clients. Recidivism rates among network clients are lower than among nonparticipating youths. Network client profiles, program costs, and client and counselor evaluations are also reported. The report recommends that the county continue funding delinquency prevention programs that take clients who are either police or probation referrals, for whom an arrest history can be demonstrated. Each of the 13 projects is profiled in terms of its costs, delinquency risk, recidivism, and referral and service characteristics. Additional cost calculations, footnotes, and data tables are provided.