While at Toronto, Havelock began formulating his theory of orality and literacy, establishing the context of a later movement at the University interested in the critical study of communication, which Donald F. Theall has called the "Toronto School of Communications". Havelock's work was complemented by that of Harold Innis, who was working on the history of media. The work Havelock and Innis began in the 1930s was the preliminary basis for the influential theories of communication developed by Marshall McLuhan and Edmund Snow Carpenter in the 1950s.