If you haven’t yet seen these secret fore-edge paintings—paintings that appear on the side of the book opposite the spine when you squish the pages into a slanted line—they’re well worth a look.
Both Flavorwire and io9 have posts with various photos, animations, and videos.
Some of the paintings are thematically fitting (a depiction of Adam and Eve on a copy of the Bible) while others are more puzzling (an image of the London Bridge on Paradise Lost), but they’re all stunning.