The Book of the Dead is similar to the Udjat Eye, in the way that its main purpose is to help the user locate a secret level exit to take them to bonus stages.
In Olmec's Lair on level 4-4, there will be a secret door somewhere just above the lava at the bottom of the map which leads to Hell. It will only be accessible when the Spelunker has the Book of the Dead in their inventory.
Once again comparable to the Udjat Eye, the Book in the player's HUD will start to become agitated, seemingly laughing. The more that the face writhes, the closer the holder is to the X coordinate of the door to Hell.
To access the door, the player must defeat Olmec by causing them to fall into the lava just under the door. Once the player has baited Olmec into the lava, they may use Olmec as a platform as he sinks into the lava to enter Hell. This is the easiest way to enter the door, as there is no ledge below it and cannot be reached without something to stand on.
It is still possible in certain circumstances to push a pair of push blocks into the lava to use as a platform, although this relies on random level generation to be possible and still requires the Book of the Dead to initially open the door. This strategy typically is only of use to pacifist runners attempting to beat the game without being responsible for killing a single enemy, including Olmec himself.
Once the player enters Hell, the book has no practical function. The book will regardless continue writhing and laughing with increasing intensity the deeper the player travels downwards, writhing fastest inside of Yama's Throne.
- The Book's appearance is modeled after the Necronomicon depicted in the Evil Dead franchise.
- The Book of the Dead is briefly referenced in the Journal entry for the Necromancer in Spelunky 2, as they spent their entire lives studying it. This explains their ability to summon red Skeletons much like Anubis II would in Spelunky HD.