I've seen a few recent references to one of the great overlooked Gold Medal novels, The Captain Must Die by Robert Colby. If you want a feel for the real Fifties in the form of a grim caper novel, this is your book. It's tight, deftly plotted and one of those hardboiled novels that is genuinely tough without showing off.
Bob Colby was a nice guy who struggled through a four decade run as a free-lancer. He never had the hit he deserved. I wouldn't say he was major but his books usually had a nice sweaty noir desperation to them. His people were often more interesting than the stories they were involved in. He had a bittersweet sense of the failed man in a society that despises failure, the man always looking for the long chance who never seems to understand--or even anticipate--that the long chance will destroy him.
I got to know him in the last six or seven years of his life. He'd spent his early life in radio and tv and you could tell that by the smooth, almost courtly way he did business. They were gentlemen back then. His glory days were with Richard Carroll at Gold Medal. Apparently Knox Burger didn't like his stuff and he was soon shuffled off to places like Monarch.
He's worth looking up. If you read nothing else, make it The Captain. It's damned fine book.