The tangled relationship between education research and policy has received little serious scrutiny, even as paeans to "scientifically based research" and "evidence-based practice" have become a staple of education policymaking in recent years. For all the attention devoted to the five-year-old Institute of Education Sciences, to No Child Left Behind's (NCLB) call for "scientifically based research," to professional interest in data-driven decision-making, and to the refinement of sophisticated analytic tools, little effort has gone into understanding how, when, or why research affects education policy. Instead, most discussion has focused on how to identify "best practices" or "scientifically based" methods and how to encourage classroom educators to use research findings. In "When Research Matters: How Scholarship Influences Education Policy," a new book published by Harvard Education Press, Frederick M. Hess has collaborated with a team of leading scholars to examine these questions. (Contains 12 endnotes.)