Maybe I dreamed it but I could swear that I read that Gödel, Escher, Bach: An Eternal Golden Braid was typeset by Hofstadter in TeX. That, by itself, although fairly amazing, wasn't the most noteworthy thing to me but that he had first read—uploaded to his brain—all the docs for TeX before he wrote a single word and let the experience of using it call forth from memory the relevant documentation.
While METAFONT, and to a lesser extent, TeX, were to become frequently featured characters in Hofstadter's Metamagical Themas days, GEB was pre-TeX. It was created using Pentti Kanerva's TV-Edit at Stanford (with the data on punched paper tape). The preface to the 20th anniversary edition of GEB tells the tale.
