The Monster Men is a 1913 science fiction novel written by American author Edgar Rice Burroughs under the working title "Number Thirteen". It first appeared in print under the title of "A Man Without a Soul" in the November, 1913 issue of All-Story Magazine, and was first published in book form in hardcover by A. C. McClurg in March, 1929 under the present title. It has been reissued a number of times since by various publishers. The first paperback edition was issued by Ace Books in February 1963.