The quote comes from pages 10-11 of Guards! Guards!
Damp darkness shrouded the venerable buildings of Unseen University, premier college of wizardry. The only light was a faint octarine flicker from the tiny windows of the new High Energy Magic building, where keen-edged minds were probing the very fabric of the universe, whether it liked it or not.
And there was light, of course, in the Library.
The Library was the greatest assemblage of magical texts anywhere in the multiverse. Thousands of volumes of occult lore weighted its shelves.
It was said that, since vast amounts of magic can seriously distort the mundane world, the Library did not obey the normal rules of space and time. It was said it went on forever. It was said that you could wander for days among the distant shelves, that there were lost tribes of research students somewhere in there, that strange things lurked in forgotten alcoves and were preyed on by other things that were even stranger.1
Wise students in search of more distant volumes took care to leave chalk marks on the shelves as they roamed deeper into the fusty darkness, and told friends to come looking for them if they weren't back by supper.
And, because magic can only loosely be bound, the Library books themselves were morethan mere pulped wood and paper.
Raw magic crackled from their spines, earthing itself harmlessly in the copper rails nailed to every shelf for that very purpose. Faint traceries of blue fire crawled across the bookcases and there was a sound, a papery whispering, such as might come from a colony of roosting starlings. In the silence of the night the books talked to one another.
1. All this was untrue. The truth is that even big collections of ordinary books distort space, as can readily be proved by anyone who has been around a really old-fashioned second-hand bookshop, one of those that look as though they were designed by M. Escher on a bad day and has more staircases than storeys and those rows of shelves which end in little doors that are surely too small for a full-sized human to enter. The relevant equation is: Knowledge = power = energy = matter = mass; a good bookshop is just a genteel Black Hole that knows how to read.↩
Special thanks to Sean for helping me with how to put footnotes in a post! It's my one thing I learned today.