This report notes that studies dating back to 1906 find that children score lower on standardized tests at the end of summer vacation than they do in the Spring when schools close. Summer programs that address the needs of the whole child seem to be most successful at boosting academic achievement, self-esteem, and confidence. They also motivate students to want to learn, and help them develop new skills and talents. The report shows how well-designed summer programs provide academic enrichment that mitigates the summer learning gap, offer experiences that aren't available during the school year, and increase educational equity for low-income families with learning opportunities that are otherwise more readily available to affluent families. (Contains 28 endnotes.)