Above: a nice cover for Frank Gruber's 1947 mystery Market for Murder, from Panther books. We don't know who painted the art, but it looks a little like Josh Kirby, and he was occasionally working for Panther when this edition came out in 1956. But don't quote us, because we're guessing with not even fifty percent certainty. You can see confirmed Kirby here and here. 

The most difficult piece of human anatomy for an artist to master, so we've heard, is the hand. But pulp icon Rudolph Belarski was so good at hands that they were often the central element of his covers. Below are seven examples culled from around the internet showing his proficiency—indeed, flaunting his ability—in this area. And you can see an eighth handsome Belarski here.