A long while ago, when playing Skyrim, I found a book in-game that explained the lore reason why Spell Tomes are destroyed when used. I've since lost the save file, and have been unable to relocate the book. I tried looking for it's name online, but could not find it, or any information or explanation for why Spell Tomes are destroyed when used. If any one could tell me the name of the book or the reason why spell tomes are destroyed when used, I would be very thankful.
Also to specify. I am looking for the lore reason for why Spell Tomes are destroyed when used. Not the gameplay mechanic reason.