The Moon Man is a fictional pulp magazine character who appeared in Ten Detective Aces magazine, published by A.A. Wyn's Ace Magazines. He was a pulp hero in the Robin Hood mold. Frederick C. Davis created the character and wrote all the stories under his own name. (Davis had a long career as a mystery novelist under various pen names, most notably "Stephen Ransome.")
The Moon Man was so named because he concealed his identity with a spherical helmet of argus glass, which gave a mirrored appearance. He wore a black robe with black gloves. Because the Moon Man robbed from villains, he was viewed by the police as another criminal. All the loot he took was instead distributed secretly to the poor of Great City by the Moon Man's ally, Ned "Angel" Dargan.
The Moon Man was really detective-sergeant Stephen Thatcher, son of Great City's Police Chief. His main opponent was Detective Gill McEwen, who worked to stop the Moon Man. Sue McEwen, Gill's daughter, was Thatcher's love interest.
A few Moon Man stories were reprinted in later years, with a proposal in the mid-1980s to reprint all the stories in two volumes from "Purple Prose Press". Only the first volume, Night Nemesis, saw print. More recently, the small press Battered Silicon Dispatch Box published the two volumes as a set.
A few new Moon Man stories have also appeared in pulp fanzines. Longer works include The Hounds of Hell, published by Airship 27, which pitted the Moon Man against pulp villain Doctor Satan.