"A Princess of Mars" by Edgar Rice Burroughs is a science fantasy novel first serialized in 1912. Confederate veteran John Carter is mysteriously transported to Mars, a dying desert planet called Barsoom. With superhuman strength from the planet's lower gravity, he becomes entangled with warlike Green Martians and rescues Dejah Thoris, a princess of the humanoid Red Martians. Carter must navigate deadly political conflicts between alien races while fighting to protect the princess and save all life on Mars from extinction.
