To understand the indefinite size of the Universal Library, you must understand what you're getting into when the Librarian says his Universal Library Algorithm (ULA) writes books.

The ULA is given a set of characters it may use, in this case every English letter, every form of punctuation, spaces, musical notation, mathematical symbol, others. Once the ULA is told to run, either independently or to write a book based on an inquiry into the Contextual-Engine, the algorithm randomly places character after character until the limit of the 'book' is reached.

You can receive back a book filled only with a's. Or pages of random words or mathematical symbols only to find more a's. Every possible permutation is possible with the ULA.

What is a 'book'? To artificially ensure the ULA would stop at some point and prevent a book from being indefinite, and of course to prevent a complete melt down of the servers, a book was defined as having a certain number of pages. The pages could hold up to a certain number of lines, and each line could be only up to a certain number of characters before needing to wrap to the next line.

Paragraphs are sometimes trouble for the ULA. 

Because of its indefinite processing, a complete copy of the Constitution for the United States could be written. So could Mother Goose books. And gibberish. But then, what is gibberish? How would you know? As it will also write books in English that were in a foreign language, or books of hummingbirds and trees talking together, translated into English, how would you know?

That is the puzzle and adventure waiting within.

Quite Literally Yours,

The Librarian