Thuvia, Maid of Mars: Illustrated

Thuvia, Maid of Mars: Illustrated (1920) is a science fiction novel by Edgar Rice Burroughs, the fourth of the Barsoom series. The principal characters are the Son of John Carter of Mars, Carthoris, and Thuvia of Ptarth, each of whom appeared in the previous two novels. While typical in many ways of Burrough's Barsoom novels, it also includes some inventive elements. 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.