This essay seeks to chart a largely unexplored psychology of religious experience in The Idea of the Holy, which is directly related to Otto's claim that one of the most important functions of discourse about religious experience is to evoke numinous feelings in a religiously sensitive audience. It will be demonstrated that Otto's concepts of schematization of the numinous, the numinous and the rational a priori, and divination cannot be understood by phenomenologists and philosophers of religion except in the light of this claim, and that Otto intends that his concept of schematization (profoundly influenced by Fries's transcendental idealism) be identified with his law of association of analogous feelings which explains how the excitation of numinous experience is produced. Moreover, this theory of religious experience rests upon an assumption about the relationship between religious language and experience which requires elucidation and evaluation. Otto's claims about numinous experience being inexpressible and yet, paradoxically, made intelligible through the use of analogy will be critically examined in the light of recent philosophical discussion concerning the relationship between all language and experience, and it will be shown not only that Otto's ineffability language is not unintelligible, but also that he offers a sophisticated theory of analogical language which may do much to extend the boundaries of our understanding of religious experience. Furthermore, an assessment will be made of the cognitive status of numinous experience; and it will be argued that, in spite of Otto's failure to establish its cognitive certainty by appealing to his account of the numinous a priori, he successfully demonstrates that, whatever its cognitive status-may be, it is a distinctive experience which cannot be confused with any other and is easily identifiable as unmistakably religious. Finally, an attempt will be made to clarify Otto's standing within the history of phenomenology of religion.