Arcana Unearthed (properly Monte Cook's Arcana Unearthed, ISBN 1-58846-065-7) is a role-playing game created by Monte Cook and first published in 2003. Described as a "variant player's handbook", the 256-page hardcover core rulebook bears many similarities to the Player's Handbook of 3rd Edition Dungeons & Dragons, on which Cook worked a few years prior. Arcana Unearthed is based on the d20 system of Dungeons & Dragons, but because of the rules for character advancement, it cannot be an official d20 system product. It does, however, use the Open Gaming License.