Synthetic Men of Mars (Martian Tales of Edgar Rice Burroughs, No 9)

EDITORIAL REVIEW: John Carter desperately needed the aid of Barsoom's greatest scientist. But Ras Thavas was the prisoner of a nightmare army of his own creation -- half-humans who lived only for conquest. And in their hidden laboratory seethed a horror that could engulf all of Mars. John Carter desperately needs the help of Ras Thavas, but Ras is the prisoner of half-humans who live only for conquest. Their laboratory contains a horror that could engulf all of Mars The machine which creates synthetic men malfunctions and must be destroyed