Now there's a thoroughly bizarre cover for you. I'm not sure what's going on here, but I am certain there are some good authors in this issue of POPULAR DETECTIVE, including Hugh B. Cave, Steve Fisher, Edmond Hamilton, Barry Perowne, Emile C. Tepperman, Frederick C. Painton, and George A. McDonald. If I'd had an extra dime and nickel in my pocket back in 1936, I might've had to buy this one just to try to figure out the cover.
HEADQUARTERS DETECTIVE is a pulp that lasted only a few issues, but there were some good writers in its pages. This one features stories by Frederick C. Davis, George Harmon Coxe, Steve Fisher, Norman A. Daniels, and George A. McDonald, among others. With a lineup like that, I'm sure it was good reading.
This cover has enough going on that I thought for a moment it might be Norman Saunders' work, but at the same time it doesn't really look like him to me. Maybe someone reading this can provide a definite answer. At any rate, it's a good cover and I like it. The lead novel in this issue of THRILLING DETECTIVE is by John Benton, a Thrilling Group house-name. Norman Daniels was often Benton, but not always. Since there's a story in this issue under his name, I think he's the most likely suspect. But George A. McDonald, who wrote some good Phantom Detective novels and the Lynn Vickers, G-Man, series, is also in this issue under his name, and he was a Thrilling Group stalwart, so he might have been Benton this time, as well. Or somebody else entirely. Who knows?