This issue of Medieval Philosophy and Theology is atypical in that it contains a single work by a single philosopher and scholar. Norman Kretzmann, the author of the work here presented, was one of the founders of this journal and served as the chair of its editorial board from the journal’s inception until his untimely death in 1998. His intimate association with Medieval Philosophy and Theology and his dedication to its mission makes the journal an entirely appropriate vehicle for the publication of the work that filled the last year of his life.