Alternate Oz is a term that has been widely applied to modern Oz fiction that departs in significant ways from the pattern set by the works of L. Frank Baum and his successors as Royal Historians of Oz. The term Dark Oz has also been applied to some of these works. In his influential critical essay "The Other Oz," Stephen Teller proposed a fourfold division of the total Oz literature. His fourth and last category is the "Heretical Apocrypha," consisting of Oz fictions that depart from the established Oz narrative, or are inconsistent with, of overtly contradict, its spirit and tone.