The Free Library of Philadelphia's Literacy Enrichment Afterschool Program (LEAP) is a key part of Philadelphia's comprehensive citywide Out-of-School Time (OST) system. For more than 25 years, the Free Library has offered children academic support and enrichment through LEAP, a free, voluntary, and drop-in program. At the request of the Free Library of Philadelphia, Policy Studies Associates (PSA) conducted an evaluation of LEAP during the 2018-19 program year. Focused on the experiences of LEAP participants in PreK-3, the evaluation explored a central hypothesis: Drop-in programming in a literacy-rich environment can help young people develop the skills they need to succeed in school and beyond. Drawing on data collected through interviews with LEAP staff and librarians, program observations, surveys of students and of staff, and analysis of participation records, the evaluation explored the contribution of LEAP to the citywide OST system and the benefits of LEAP participation. Key findings and recommendations for further strengthening the program are summarized. [For briefs that share findings for program staff (ED605327), funders and policymakers (ED605326), and library leaders (ED605325).]