Arcana Unearthed is a popular role-playing game created by Monte Cook. Described as a "variant player's handbook", the Arcana Unearthed core rulebook bears many similarities to the Players Handbook of 3rd Edition Dungeons & Dragons, on which Cook worked a few years prior. In terms of rules, Arcana Unearthed is based on the d20 system of Dungeons & Dragons, although it is not an official d20 system product.

Two of the most important areas of focus in the game are ritual and character choices. Many special abilities are gained by the character going through ceremonies. Two particularly interesting examples are metamorphosis, in which faen become tiny, winged sprytes, and Chi-Julud, in which the wise giants temporarily lose their wisdom to become stronger and more warlike. These examples typify the choices that are built into every aspect of the game, including character race. Cook emphasizes that players should avoid archetypes (presumeably referring to the character archetypes of Dungeons & Dragons) and design their characters more creatively. In fact, shortly after the game was released, Monte Cook's website, www.montecook.com, held a character design competition.

The campaign setting for Arcana Unearthed is the lands of The Diamond Throne, a land ruled by giants. The setting includes many elements of a traditional fantasy setting, along with a focus on ritual and ceremony, runes, and the magical properties of crystals.

Arcana Unearthed is not to be confused with Unearthed Arcana: two books published in 1985 and 2004 which provide additional material for use in Dungeons & Dragons games.