I read somewhere recently that the idea for The Fat Man radio series originated with Hammett's agent, and was pitched as Casper Gutman playing detective. As preposterous as that idea is, I have no reason to think it isn't true. Gutman was referred to as the Fat Man in The Maltese Falcon, and even had a chapter named after him. On the other hand, the character bears slightly more resemblance to the Continental Op, who also sometimes referred to himself as a fat man. The only thing that really makes sense is that it was a clever way to capitalize on the popularity of the Thin Man franchise, and pretend the character was really a creation of Hammett's.
Anyway, Universal made a movie of it, and while this isn't the worst film ever made, neither was it good enough to spawn After The Fat Man, or Another Fat Man, or The Fat Man Goes Home, or Shadow of the Fat Man, or even Song of the Fat Man. Oh well. You should watch it anyway. Did you know Julie London once recorded a sultry version of "Louie, Louie"? You didn't? See below.
More Overlooked Films at Sweet Freedom