It simulates combat in the fantasy world of Barsoom, originally imagined by Edgar Rice Burroughs in his series of novels about John Carter of Mars.
It is a 56-page booklet in the same style as the original Dungeons & Dragons books, even sharing the same artist Greg Bell.
[1] Gygax and TSR published the rules without permission from Burroughs estate and soon after its release they issued a cease and desist order and the game was pulled from distribution.
[1][2][3] Because only a few copies were sold the book is now rare and sells for a high price.
[1][2] The same year Warriors of Mars was published (and then un-published), Gygax published the first edition of Dungeons & Dragons, where he paid homage to Burroughs in the last paragraph of the "Preface": This wargame-related article is a stub.