The Ar tonelico: Melody of Elemia Setting Encyclopedia is a large encyclopedia for Ar tonelico: Melody of Elemia authored by the GUST Staff and supervised by both the Producer and Director of the series, Atsunori Kawachi and Akira Tsuchiya, which compiles a large amount of the information used during the development of the game about its world and characters, which was released with the aim of answering questions about several aspects that were left unexplained during the course of the game. It's also known among the fandom by the Settei Book name.