The Iron-Bound Books of Shuma-Gorath first appeared in print in "The Curse of the Golden Skull" by Robert E. Howard which was published in 1967. It was first mentioned in Marvel Comics in 1974 in Conan the Barbarian Vol 1 37 and first made a visual appearance in Conan the Barbarian Vol 1 258. They have also been mentioned in the Conan: Adventures in an Age Undreamed Of role-playing game by Modiphius Entertainment.
The Iron-Bound Books of Shuma-Gorath are tomes of mystic lore. With which one can become the master of the world. The clasps on it are enchanted and cannot be opened either by sorcery or sword. To unlock it's secrets, requires a key. They were magically created by humans long before the first books existed. The book was created from iron plates and rings. It was used by the sorcerers of Pre-Cataclysmic Lemuria to summon magical power for their spells.