Swords of Mars was first published in Blue Book magazine (November 1934 – April 1935). The first hardcover edition was published by ERB, Inc Tarzana, February 15, 1936. The dust jacket and five interior plates were done by J. Allen St. John.
John Carter decides he must put an end to the Assassin's guild in Zadonga and so creates his own organization of super-assassins. Then when Dejah Thoris is kidnapped, he must travel to the moon of Thuria to rescue her.