This Wallace Foundation topic page offers prevention professionals a curated hub of resources—including articles, reports, briefings, tools, and multimedia—focused on building and sustaining high‑quality afterschool and summer learning systems. It highlights proven system‑building initiatives in more than a dozen U.S. cities, outlines four essential elements for effective afterschool systems (committed leadership, coordinated infrastructure, data‑driven decision‑making, and program quality efforts), and shares research demonstrating how systemic coordination increases access, boosts attendance and academic gains, and supports social‑emotional development in underserved youth. Ideal for professionals looking to integrate prevention strategies into afterschool models, the page provides actionable frameworks, funding guides, and policy briefs designed to inform partnership building, community alignment, and sustainable youth engagement efforts.