The Chessmen of Mars by Edgar Rice Burroughs is the fifth novel in the Barsoom series. It was published as a 6-part serial between February and March of 1922, before being released as a complete novel in the November of the same year. As of 2020, this is the last Barsoom novel in the public domain. Assuming no changes in copyright law, we can expect to see A Fighting Man of Mars, published in 1928, enter the public domain on January 1st, 2024.
The heroine of the story is Tara, the daughter of John Carter and Dejah Thoris. Gahan, prince of Gathol, wants her hand in marriage. Tara is against this; she doesn’t see him as a suitable partner, thinking him a dandy. One day, when shes out on her flier, a storm strands her in an unknown area. While Gahan seeks to rescue her, she comes across Kaldanes and Rykors, grotesque creatures that don’t have anything nice planned for Tara.
Some things never change - one of them being Edgar Rice Burrough’s man-saves-woman trope. Tara, now a damsel in distress (save one Kaldane who is enamored with her singing), now needs Gahan to rescue her.
The name of the novel comes from the game Jetan, which is similar to chess here on Earth, and features prominently in the book. It is similar to the chess game played in Harry Potter and the Sorcerer’s Stone, except its played with actual people (well, Martians) who must duel to the death if they occupy the space of another piece.
Burroughs’s vision of mars was adapted from speculation put forth by Percival Lowell, who put forth the theory that there were canals on Mars. Lowell thought that Mars used to be like Earth but time had ravaged it to its current state. The canal theory came to be thanks to a mistranslation of the Italian canali, which meant channels.