The Monster Men (Ace SF Classic, F-182)

They called him Number Thirteen, the latest and best of Dr. von Horn's attempts to create life from chemicals. He found himself an almost-human on von Horn's hideaway jungle island off the coast of Borneo. He saw the monsters that had preceded him and grew used to those dreadful travesties of humanity. Not until Number thirteen met the American girl who was von Horn's prisoner did he realize how different he was from the others. Then, monster or not, he turned against his master and his "brothers" and threw in hhis lot with the girl in a desperate attempt to escape the island of terror. First paperback printing, Ace F-182