For more than a century, researchers have known that students lose ground over the summer. Yet insights about solutions for the loss have been slower to emerge. That is beginning to change, owing in part to The Wallace Foundation’s $60 million National Summer Learning Project. Launched in 2011, it included five urban districts and their partners, and a wide-ranging study by the RAND Corporation that is the largest ever undertaken on summer learning. This Wallace Perspective distills key lessons from that work for district leaders, out-of-school time providers and intermediaries, and funders to consider. For more information, visit wallacefoundation.org