The mysterious Ouija board has long epitomized the fear and curiosity people feel toward the unknown. Noted as being used by Pythagoras as early as 540 B.C., ouija boards came to more popular attention in the nineteenth century when they were played as parlour games. Ouija boards are used by one or more people who place their fingers lightly on the indicator, which moves across the wooden board, seemingly involuntarily, from letter to letter, making words or sentences. The messages created during the game have been described as links to the spiritual world and/or the subconsciousness of the players.

The modern ouija board was invented to ease the process of what believers thought of as communicating with the beyond. Its predecessors included the "automatic writing" of nineteenth-century French spiritualist M. Planchette and the system of raps (one for no, two for yes) devised by the...