Empowered Elven Tome

Before the various Class Orders started working closer together, this item was used to gain new knowledge about artifacts and increase the rate at which Artifact Power was earned.

Source
This item was a quest reward from the following quests:
 * Delivering Lost Knowledge (death knight)
 * Delivering Lost Knowledge (monk)
 * Delivering Lost Knowledge (mage)
 * Delivering Lost Knowledge (paladin)
 * Delivering Lost Knowledge (warrior)
 * Delivering Lost Knowledge (hunter)
 * Delivering Lost Knowledge (shaman)
 * Delivering Lost Knowledge (druid)
 * Delivering Lost Knowledge (warlock)
 * Delivering Lost Knowledge (priest)
 * Delivering Lost Knowledge (demon hunter)
 * Delivering Lost Knowledge (rogue)