"Tlön Uqbar Orbis Tertius" is the title of a short story by the Argentine writer Jorge Luis Borges that revolves around a rare (possibly unique) edition of the Encyclopedia Britannica containing an entry on an otherwise unknown country called Uqbar. As the story unfolds, it appears that Uqbar is part of a conspiracy of thinkers to create an entire new world, Tlön, by imagining it in all its details.
Borges's story is self-consciously literary in that it both puts an imagined world in play (as does all fiction) and comments overtly on worldmaking as a process. Especially striking is the degree to which it both depends on and includes entries from the fictive encyclopedia. Many stories and novels use transcriptional elements in this way-- they might include a love poem written by the narrator, or the text of a message slipped under a door. The more extensively such elements are used, the closer the affinity between such works and fictive art. At the extreme, where the novel becomes another kind of thing altogether, one finds epistolary novels like Richardson's Pamela, document-based novels like Doris Lessing's Sirian Experiments (which is constructed as a series of bureaucratic reports), and the fully encyclopedic novel Dictionary of the Khazars by Milorad Pavic.