Paul W. Fairman was the founding editor of If magazine but left after only four issues, if Wikipedia is to be believed, anyway. This is a noir novel copyrighted 1967, about 10 years before his death. (I believe it's bound to be the same Paul W. Fairman, anyway.)
It's published by Lancer Books, obviously, if you glance down a bit. That's an early imprint from the late Walter Zacharius, who went on to found Kensington Books. It was under Kensington's Pinnacle imprint that my novels originally appeared. Six degrees, I guess. I don't know that I knew that when I bought this years back.
Dead City, an earlier tale from Mr. Fairman and basis for the film Target Earth, now at Project Gutenberg