The Monster Men is a 1913 science fiction novel by American author Edgar Rice Burroughs, written under the working title "Number Thirteen". It first appeared in

The Monster Men is a 1913 science fiction novel by American author Edgar Rice Burroughs, written under the working title "Number Thirteen". It first appeared in

The Monster Men is a 1913 science fiction novel by American author Edgar Rice Burroughs, written under the working title "Number Thirteen". It first appeared in

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

The Monster Men is a 1913 science fiction novel by American author Edgar Rice Burroughs, written under the working title "Number Thirteen". It first appeared in