My wife Marty pointed me to this snippet from the Discworld series last night:
The Library of Ephebe was – before it burned down – the second biggest on the Disc.
Not as big as the library in Unseen University, of course, but that library had one or two advantages on account of its magical nature. No other library anywhere, for example, has a whole gallery of unwritten books – books that would have been written if the author hadn’t been eaten by an alligator around chapter 1, and so on. Atlases of imaginary places. Dictionaries of illusory words. Spotters’ guides to invisible things. Wild thesauri in the Lost Reading Room. A library so big that it distorts reality and has opened gateways to all other libraries, everywhere and everywhen …
–Terry Pratchett, Small Gods (1992)
See my other posts related to the parallel world of Loka.