The Monster Men (Ace SF, 53590)

Third Ace edition, from the early 1980s. They called him Number Thirteen, the latest and best of Dr. von Horn's attempts to make life from lifeless chemicals. He became aware of himself as an almost-human on von Horn's secret jungle island off the coast of Borneo. He saw the monsters that had preceded him and grew used to these dreadful travesties of humanity. Not until Number Thirteen met the American girl who was von Horn's unwilling prisoner did he realize how different he was from the others. Because, monster or not, he turned against his master and throw in his lot with the girl and his friends in their desperate attempt to escape from an island of terror