Thuvia Maid of Mars

Thuvia, Maid of Mars is a science fiction novel by Edgar Rice Burroughs. The principal characters are the Son of John Carter of Mars, Carthoris, and Thuvia of Ptarth. In this novel the focus shifts from John Carter, Warlord of Mars, and Dejah Thoris of Helium, protagonists of the first three books in the series, to their son, Carthoris, prince of Helium, and Thuvia, princess of Ptarth. Helium and Ptarth are both prominent Barsoomian city state/empires, and both Carthoris and Thuvia were secondary characters in the previous novel. Its plot devices are similar to the previous Martian novels, involving the kidnapping of a Martian princess. It does however have some inventive and original ideas, including an autopilot and collision detection device for Martian fliers, and the creation of the Lotharians, a race of ancient martians who have become adept at telepathic projection, able to create imaginary warriors that can kill, and sustain themselves through thought alone.