Atelier Sophie: The Alchemist of the Mysterious Book is a 2015 Japanese role-playing video game developed by Gust for the PlayStation 3 (only in Japan), PlayStation 4, PlayStation Vita (digital-only) and Microsoft Windows. It is the 17th main game in the Atelier series and the first game of the Mysterious storyline, as well as the debut of Koei Tecmo taking over publishing rights for Western regions in place of NIS America. The enhanced version of the game titled Atelier Sophie: The Alchemist of the Mysterious Book DX was released for PlayStation 4, Windows, and the Nintendo Switch on April 22, 2021.