International relations specialists have frequently questioned whether their academic research and teaching has any impact on the "real world." The record of success is generally believed to be a spotty one. While there is no denying that academics have informed aspects of policymaking, the concern remains that the great bulk of international studies research is too abstract, specialized, or linguistically incestuous to reach the light of day in policy circles. We argue that the relationship between the pursuit of peace and security and the study of it is more complex than is captured by the classic policy-research divide. The argument rests on two observations: First, to assess the public impact of peace and security studies, one must focus on how practices within a variety of institutional contexts, not just state policies, are transformed. Second, it is not scholarship per se that has a measurable public impact, but the interplay of research, practical innovation, and advocacy. We derive these observations from a review of the work of Social Science Research Council-MacArthur Program fellows over the fifteen-year life of that program.We live in an age when U.S. academic departments and research programs are often obligated to demonstrate to administrators and funders that what they do has an impact on the world beyond the academy. For the field of International Relations this task has been less menacing than it has been for fields like Comparative Literature. The subject matter that occupies IR scholars is often selfevidently central to the well-being and security of millions of lives everyday.Yet IR specialists have worried quite a bit about whether what they write and teach has any impact on the "real world" pursuit of peace, security, and human well-being~Newsom, 1995-96!. The concern has been well-founded historically. After all, not only were grave official decisions of war and peace often at issue in their work but so too were decisions about governmental funding of academic research programs. Over the past 50 years millions of research dollars have ridden on the persuasiveness of claims about "policy relevance" in research proposals~Geiger, 1993; Lowen, 1997!.International Studies Perspectives~2001! 2, 221-230.