John Carter of Mars
John Carter of Mars technically refers to the main protagonist of the Barsoom Sword & Planet novels written from the 1910s onward by Edgar Rice Burroughs, but is commonly used to refer to the Barsoom universe as a whole.
Basic Summary
The Barsoom books revolve around an adventurous Virginian man named John Carter, who is somehow mentally projected to Mars - a dying world of red deserts and rocky badlands inhabited by myriad alien races, who collectively refer to their world as "Barsoom". Filled with a spirit of adventure and a "good ol' boy" sentiment, and granted superhuman strength by Barsoom's lighter gravity, John Carter becomes a great leader who rescues (and ultimately marries) the princess of the surprisingly human-like "Red Martians", ultimately going on to bring peace to Barsoom by uniting its once-warring cultures as the Warlord of Mars.
Barsoom Lore
(Insert details on Barsoom and the various Martians here)
A Winning Formula
Barsoom was a huge hit, so much so that not only did Burroughs himself try to repeat his success with the Carson of Venus series, but at least two other major pulp novel series were born out of the style.
A writer called Leigh Brackett created the Eric John Stark stories, originally as pulp magazine novellas in Planet Stories from 1949 to 1951, before rewriting them several times over up until the 80s; Eric, who combines and arguably slightly parodies elements of both John Carter and Tarzan, is the son of space-miners who died in a cave-in, leaving their child to be adopted and raised to maturity by the primitive humanoid aliens of the Mercurian Twilight Belt... who were killed by space pirates when Eric was a teenager, who would have killed him in the same way if a space cop hadn't shown up and rescued him. Skin burned a deep, glossy black by the intense sunlight of the Twilight Belt, Stark's origins made him intensely empathic towards the plight of the enslaved and oppressed aliens of the Solar System in the face of the colonizing Human powers, and he fought against them.
Then along came John Norman in the 1970s, whose Gor novels start out with the Barsoom formula, with an ordinary Earth guy being snatched away to a primitive, warlike "Counter-Earth" secretly ruled over by highly advanced insectoid aliens and becoming a much-respected warrior... then quickly devolved into exulting our protagonist and all his friends being a psychopathic bunch of misogynists who run around raping any woman who dares to think she has a life outside of cooking, cleaning and being a sex-toy.
The Games
Whilst the Barsoom books had their influence on Dungeons & Dragons - the Girallon is based on a Barsoom monster, whilst Dark Sun is basically copying Barsoom's aesthetic - the books actually have their own roleplaying games.
The first, John Carter, Warlord of Mars, is an RPG that was published by Heritage Models in 1978.
A year later, Simulations Publications, Inc would produce a John Carter: Warlord of Mars board game.
In 2015, Modiphius announced their plans to revive John Carter as both an RPG (using their new "Momentum" ruleset, a lighter version of their original 2d20 RPG system), a board game, and a miniature warband game.