For those of us who have been blessed with an understanding of this regulation we call copyright, the lawyers representing the Mitchell estate were uttering something completely understandable.A sequel is a derivvative work. The owner of a still live copyright, that is, one that has not yet expired, controls the rights of others to produce derivative works. To write and publish a counterstory to Margaret Mitchell’s, you need the permission of the Mitchell estate. Not the author–she’s sadly long dead–but the estate. At least until the copyright expires, though the idea of copyrights expriing seems itself an expired idea.
Had Mitchell’s copyright expired on its original schedule, it would have fallen into the public domain in 1993…But Congress has turned against this idea that copyrights expire. It is drunk on the idea that it can extend “limited terms” as often as it wants. In fact, eleven times in the last forty years, Congress has extended the term of subsisting copyrights. Its latest extension was in 1998, extending existing terms 20 years.
Cardozo Arts & Entertainment Law Journal