The novel tells of earthman John Carter who is mysteriously transported to the planet Barsoom (through a species of teleportation), and encounters both formidable alien creatures resembling the beasts of ancient myth and various humanoids, from the "Red Martians" who resemble Homo sapiens in almost every respect except that they are oviparous, to the "Green Martians", four-armed, tusked, and approximately four meters tall. Barsoomians are generally warlike and honor-bound. The technology of the tales runs the gamut from dueling sabers to ray guns and aircraft, with the discovery of powerful ancient devices or research into the development of new ones often a plot device. The natives also eschew clothing other than jewelry, providing a stimulating subject for illustrators of the stories.
Although loosely inspired by astronomical speculation of the time that pictured Mars as a formerly-Earthlike world now becoming more inhospitable to life, Burroughs' Barsoom tales never pretended to be anything other than exciting escapism.
These exciting stories caught the interest of many readers, helping to inspire serious interest in Mars and space exploration. Many later science fiction works, from Ray Bradbury's Martian Chronicles, to the Star Wars films, to the Mars Trilogy of Kim Stanley Robinson can also be seen as a nod in Burroughs' direction. Barsoom is also directly referenced in Robert A Heinlein's novel The Number of the Beast.
The Barsoom novels are: