McLuhan's contribution to the field of communication study was widely acclaimed by popular standards while simultaneously being dismissed by those in academic circles.
McLuhan was a master of aphorisms, and like Heidegger, he loved wordplay. The title of his best-selling book The Medium is the Message is no exception. The underlying notion is that the message is greatly impacted by the delivery system.
McLuhan believed that the print revolution begun by Gutenberg was the forerunner of the industrial revolution. One unforeseen consequence of print was the fragmentation of society. McLuhan argued that readers would now read in private, and so be alienated from others. "Printing, a ditto device, confirmed and extended the new visual stress. It created the portable book, which men could read in privacy and in isolation from others" (McLuhan, 1967, p. 50). McLuhan saw electronic media as a return to collective ways of perceiving the world. His 'global village' theory posited the ability of electronic media to unify and retribalize the human race. What McLuhan did not live to see, but perhaps foresaw, was the merging of text and electronic mass media in this new media called the Internet.
McLuhan is also well known for his division of media into hot and cool categories. Hot media are low in audience participation due to their high resolution or definition. Cool media are high in audience participation due to their low definition (the receiver must fill in the missing information). McLuhan's philosophy was influenced by the work of the Catholic philosopher Pierre Teilhard de Chardin, who believed that the use of electricity extends the central nervous system.