In a culture like ours, long accustomed to splitting and dividing all things as a means of control, it is sometimes a bit of a shock to be reminded that, in operational and practical fact, the medium is the message. When first published, Marshall McLuhan's Understanding Media made history with its radical view of the effects of electronic communications upon man and life in the twentieth century. This edition of McLuhan's best-known book both enhances its accessibility to a general audience and provides the full critical apparatus necessary for scholars. In Terrence Gordon's own words, "McLuhan is in full flight already in the introduction, challenging us to plunge with him into what he calls 'the creative process of knowing.'" Much to the chagrin of his contemporary critics McLuhan's preference was for a prose style that explored rather than explained. Probes, or aphorisms, were an indispensable tool with which he sought to prompt and prod the reader into an "understanding of how media operate".