By coincidence (or was it?) I picked up this copy of the The Empty Trap at the same time I got The Only Girl in the Game. The price was right, and I figured I'd reread both of them. I didn't remember at the time, and maybe it never occurred to me on the first reading, that the protagonist in both is a hotel manager. The Empty Trap was published in 1957, three years before The Only Girl in the Game, and it's considerably shorter, maybe half as long, but I can imagine JDM thinking about them at the same time.
Because of the novel's length, there's not nearly as much in it about the running of a big hotel in a gambling town (not Las Vegas, this time, but it might as well be). The manager in both cases is young, competent, and honest. In both, he's involved with a beautiful woman, but this time she's the wife of the hotel's owner, who's not a nice man at all (just like the one in the later book).
The manager's name is Lloyd Wescott, and the book opens with him and the woman being kidnapped, tortured, and killed in Mexico. Well, Wescott isn't killed. He's supposed to die, but he doesn't. Instead, he's seriously injured and mangled when the car he's in is pushed over a cliff. He's found by a youngster and taken to a remote village where he's nursed back to health. He stays there and eventually gets back in shape by doing hard physical labor. His plan is to return and kill the men responsible for the death of the woman and his own suffering. There's a lot of filling in of backstory before he recovers, and a lot of dialogue with the noble men of the village. The thing is that back in 1957, plenty of readers would've bought right into all of it, and maybe still would. It didn't bother me in the least. I suspect I knew even when I read it the first time, I knew where it was headed, but I didn't mind that, either. MacDonald could really put together a story.
The book was originally published by Popular Library and went through two printings there. I have no idea how many times Fawcett reprinted it, but it was a lot.