Although Abraham Merritt's 1928 novel (serialized the previous year in Argosy) is technically set in the "real world," namely modern New York City, much of its action takes place within the labyrinthine mansion of the crime lord known only as Satan, where the laws of reality seem, if not wholly in abeyance, at least more flexible than they are outside its walls. Seven Foot Prints to Satan tells the story of James Kirkham, an explorer who is kidnapped by thugs in the employ of the aforementioned crime lord. Taken back to his lair -- a D&D-style dungeon before the fact, complete with death traps -- Kirkham is forced to undergo a test at Satan's hands, where he must walk upon seven glowing footprints. Depending on which ones he walks upon, Kirkham will either be rewarded, executed, or bound to servitude to Satan for one year.
Our hero avoids death but he does not escape servitude and so must spend the next year engaged in a series of spectacular crimes at the behest of Satan, during which time he meets -- and falls in love with -- Eve, a young woman who shares his predicament. The crime lord is a disfigured man of astounding intellect and it's initially not clear whether his moniker is merely a nom de guerre or an indication of his true identity. Regardless, he's actually a fascinating character, in many ways far more interesting than either Kirkham or Eve, both of whom possess conventional pulp heroic personalities.
Gygax doesn't list this book by name in Appendix N, perhaps understandably since it's set in the 20th century and doesn't have any overt supernaturalism to it. Still, Satan would make a fine villain in a fantasy story and his mansion reminds me of the maze-like dungeons of the early days. There's thus a lot in its pages to inspire referees looking for a slightly different approach to dungeon design than is common nowadays. Seven Foot Prints to Satan was adapted into a film in 1929. I have never seen it, but my understanding is that it's a fairly loose adaptation. Just goes to show that Hollywood has been doing what Hollywood does for a lot longer than any of us have been alive to curse them for it.