After-school programs can play an important positive role in the academic and personal development of young people, especially in an era when many parents work full time. Launched in 1997, the Extended-Service Schools (ESS) Initiative helped establish after-school programs in 17 communities across the country, each of which adapted one of four program models to local circumstances and needs. In this report, Public/Private Ventures and MDRC present the findings from their joint evaluation of the initiative, focusing on ESS programs in six cities where intensive data collection was conducted. Among the themes examined in the report are the programs' implementation, quality, and cost and their effects on students' after-school participation and attitudes toward school.