If you are a fan of comic books than you must know what an impact Jack Kirby was to the comic book medium. He single-handily established the Marvel style and was it's greatest character creator. He was responsible for the creation of the Avengers, X-Men, Fantastic Four, Hulk, Thor and more. It appears that their was a provision for creators to get copyrights back under certain circumstances but such was not the case for Kirby's heirs.
See link below for details:
http://www.animationmagazine.net/people/judge-rules-for-marvel-in-kirby-heirs-copyright-claim/
It is important for artists / content creators to know about copyrights and contracts; especially work for hire arrangements and intellectual property clauses. That is a topic to discuss in a post coming soon.