In order to demonstrate Walton J. Ong's continuing relevance to the field of rhetorical theory, a review of his intellectual contributions and development is conducted in three stages, covering not only Ong's books and major articles but also his Jesuit educational history and his reviews of other theorists. In the first period (1939-1950), Ong's involvement with New Criticism under the tutelage of Marshall McLuhan produces critical writings concerned with close textual analysis and (in opposition to New Criticism) an emphasis on the personal and historical context of the work. In the middle period (1950-1967), Ong's concern with the "shifting sensorium"--the move from a sound oriented noetic to a sight orientation--also originates with McLuhan, who introduced Ong to Ramus studies in 1939. This "aural-visile" approach to intellectual history diverges from the views of "traditional rhetoricians," as is evident in the debate between Ong and elocution theorist W. S. Howell, in which Ong's argument explains how elocutionism arose, paradoxically, out of the new subjugation of oral delivery to the inscribed word. In the third period (1967-present), Ong's work on the transformation of the word from orality, to literacy, to electronics, contributes to a common jargon for the issue of media shifts and the accompanying change in mental processes, with McLuhan, E. A. Havelock, and A. B. Lord reciprocal influences in Ong's orality and literacy perspective. The interdisciplinary, diachronic and metarhetorical aspects of Ong's career make him one of the prominent rhetorical theorists of the twentieth century. (JG)