"A Princess of Mars" is the first book in Edgar Rice Burroughs' "Barsoom" series, introducing readers to John Carter, a Civil War veteran who mysteriously transports to Mars, known to its inhabitants as Barsoom. Here, Carter discovers a world of warring factions, strange creatures, and advanced civilizations. He becomes embroiled in local politics, battles, and romance, particularly with the titular character, Dejah Thoris, a Martian princess. The narrative combines elements of adventure, romance, and science fiction, setting the stage for Carter's many further adventures on the red planet.