Paul McCold and Ted Wachtel begin this essay by remarking that the development of restorative justice has been more by discovery than invention. Put succinctly, practice has led theory. Nevertheless, argue the authors, if restorative practices are to improve and if others are to learn from them, the social sciences have a vital role to play by providing description, theory, and evaluation. Practices should be evaluated before they are proposed as standards or as legislative mandates. Research is needed to keep a “mythology" of restorative practices from arising based chiefly on personal or political preferences. The scientific method should be used to develop a valid restorative justice theory. Hence, in this essay, McCold and Wachtel examine a theory of restorative justice constructed around a “social discipline window," a typology of restorative practices, measures of restorativeness, and tests to evaluate the validity of their theory.