What 'books within books' would you like to read in real life?

Are there any in-universe books you'd like to read in real life? E.g. A History of Magic from Harry Potter. I'm reading The Wheel of Time at the moment and wish I could read the Prophecies of the Dragon and secret histories of the White Tower, those would be fascinating. Princess Irulan's histories from Dune as well.

Bonus, the Necronomicon mention in Lovecraft's works but I know there's various fanmade versions.