Legendary comic book artist Jack Kirby was the creator or co-creator (along with the equally famous Stan Lee) of some of Marvel Comics' greatest superheroes, including the Hulk, the Fantastic Four, Thor, Iron man, the Avengers, X-Men, and more. However, while Stan Lee was an employee of Marvel Comics, Kirby was treated as a freelance artist. This means that Kirby "sold" the copyright to his work every time he accepted payment from Marvel for the pages he drew, so he did not collect royalties for the work he did, nor does his family collect royalties now on the huge amount of money made from these characters in comics or films. (Jack Kirby died in 1994.)
On September 29th, the U.S. Supreme Court was expected to decide whether or not they would hear the case in which the family of Jack Kirby disputed Marvel Comics' (now owned by Disney) copyright on the creations of Jack Kirby. (According to the Copyright Act of 1976, if one sold one's copyright to someone else prior to 1978, one could file to terminate their copyright after 56 years, and that is what the estate of Jack Kirby did.) It was expected to be a landmark case in copyright law. It will never be heard, because Marvel Comics has settled the case (on September 26th), just days before it might have gone to the Supreme Court Justices.
To read about this, one might consider these articles in the news:
How the Supreme Court and Jack Kirby Could Change Everything.
Marvel and Jack Kirby Family Settle Long-Running Legal Dispute.
Marvel and Jack Kirby Heirs Settle Legal Dispute Ahead of Supreme Court Showdown
The best summation of the copyright law involved is probably the article:
Ten Things We Should Know All About Know About Copyright Law Thanks to Kirby v. Marvel
Wikipedia has information on Jack Kirby's life and career in general.
For information on copyright law, see the Massachusetts Trial Court Law Libraries web page "Law on Copyright".