Synthetic Men of Mars, Paperback

John Carter, mighty Warlord of Mars, rides to new and terrifying adventures. Captured by deadly warriors mounted on huge birds he is taken to the ill-omened city of Morbus. There he meets Ras Thavas, evil genius and master surgeon. A man who has succeeded in his nightmare wish of creating life in his own beings - creatures that ultimately rebel and threaten the lives of Ras Thavas, of John Carter and all of Mars