I've always suspected that Henry Kane's P. I. protagonist, Pete Chambers, worked for more paperback publishers than any other P. I. ever did. I'm not going to enumerate them all there, but there were a lot of them after Chambers left hardcovers. (The hardcovers were reprinted by Dell.) In 1955, Chambers was working for Avon, and this is another one of those editions in which the print is so tiny that even the whippersnappers will be considering a magnifying glass.
Not everyone is fond of Kane's wise-cracking style, but I like it in small doses, and this is one of my favorites among his books. It's a medium-boiled locked-room story. There aren't a lot of those around, and I don't think it should languish in obscurity. For that matter, there are a lot of Kane's novels that deserve a second look. I'm not so sure about the ones he did for Lancer when he was trying to cash in on the sexy success of books like The Man From O. R. G. Y., but the others are worth a look if you're interested in something a little different in the P. I. vein.