Book excerpt: When Research Matters considers the complex and crucially important relationship between education research and policy. In examining how and under what conditions research affects education policy, the book focuses on a number of critical issues: the history of the federal role in education policy; the evolving nature of educational policy research; the role of research in debates about reading, NCLB, and “out-of-field” teaching; how research affects policy by shaping public opinion, judicial rulings, and the decisions of district and school leaders; and the incentives that help explain the behavior of researchers and policymakers.