Apparently, McLuhan also had some ideas about how to browse a book. "Marshall McLuhan, the guru of The Gutenberg Galaxy" (1962), recommends that the browser turn to page 69 of any book and read it. If you like that page, buy the book." Such apparent arbitrariness fits with picking a particular piece (or part) of a mosaic and deciding if you like it. Certainly the McLuhan test can be applied to the Gutenberg Galaxy itself. Doing so will reveal a further insight into the purpose of his own book.