John Carter, a Confederate veteran of the American Civil War, goes prospecting in Arizona immediately after the war’s end. Having struck a rich vein of gold, he runs afoul of the Apaches. While attempting to evade pursuit by hiding in a sacred cave, he is mysteriously transported to Mars, called “Barsoom” by its inhabitants. Carter finds that he has great strength and superhuman agility in this new environment as a result of its lesser gravity and lower atmospheric pressure. He soon falls in with a nomadic tribe of Green Martians, or Tharks, as the planet’s warlike, six-limbed, green-skinned inhabitants are known. Thanks to his strength and martial prowess, Carter rises to a high position in the tribe and earns the respect and eventually the friendship of Tars Tarkas, one of the Thark chiefs.
collected in three books
first here
second here
third here