Richard Allington reviews the nature of the reading achievement gap between students from low-income and high-income families, concluding that the limited access to children's books experienced by children from low-income families lies at the base of the problem. The fact that children from low-income families lose reading achievement every summer largely explains summer reading loss. Allington and his colleagues completed two large-scale studies assessing the impact of giving free books of their choice to students from low-income families for them to read over the summer. After three years of summer books, the children gained almost a year in reading achievement compared to the students who did not receive books. The summer books project cost far less than a summer school program and produced greater achievement gains than having low-income children attend summer school programs.