"Gideon the Ninth" is a fantasy novel by Tamsyn Muir, published in 2020 as the first book in "The Locked Tomb Series." With a focus on science fiction, action & adventure, space opera, and epic fantasy, this novel is intended for young adult audiences. The paperback edition has a first edition publication year and spans 496 pages. The story follows Gideon, a robot with a strong will and a love for adventure, as he navigates through an action-packed and visually stunning journey in outer space.