This issue of "New Directions for Evaluation" addresses thetopic of evaluation policy, especially how it is informed by andaffects evaluation practice. An evaluation policy is any rule orprinciple that a group or organization uses to guide its decisionsand actions when doing evaluation. Every group and organizationthat engages in evaluation, including government agencies, privatebusinesses, and nonprofit organizations, has evaluation policies.Sometimes they are formal, explicit, and written; at other timesthey are more implicit and ad hoc principles or norms that havesimply evolved over time. Evaluation policy is a criticallyimportant issue for the field and profession of evaluation.Evaluation policies profoundly affect the day-to-day work of allevaluators. Many recent and current controversies or conflicts inthe field of evaluation can be viewed, at least in part, asstruggles around evaluation policy. The chapters in this issueconsider evaluation policy in its many and varied settings andcontexts, including extensive treatment of large-scale nationalevaluation policy both in the United States and in Europe. Theissue brings together revised and extended versions of all of thekey addresses in the presidential strand of the 2008 AmericanEvaluation Association conference, including the presidentialaddress, plenary speeches, and expert lectures. This is the 123rd volume of the Jossey-Bass quarterly thematicjournal "New Directions for Evaluation, " an officialpublication of the American Evaluation Association. The journalpublishes empirical, methodological, and theoretical works on allaspects of evaluation. Each issue is devoted to a single topic, with contributions solicited, organized, reviewed, and edited by aguest editor or editors. Issues may take any of several forms, suchas a series of related chapters, a debate, or a long articlefollowed by brief critical commentaries