Eddie Mannix is also a character (played by Josh Brolin) in Hail, Caesar.
It's a made-up story, but some of the subplots may be based on real-life.
Thanks, that is the general impression I got of the movie but did not really know.
They had some of the old Superman shows on one of the nostalgia networks and I enjoyed seeing them again. I got the impression that they were interesting and well written with unusually bad special effects even by 1950s standards.
Time to rewatch LA Confidential starring Russell Crowe as a crooked cop in Hollywood.