While you don't think of crime-ridden Chicago as a haunt of the greatest detective in fiction, a major legal case involving Sherlock Holmes was decided only a week ago.
Since the tales written by his original author, Sir Arthur Conal Doyle, were penned from 1881 to 1927, according to American copyright law, all the stories written before 1923 are now "public domain", meaning that anyone can reprint them, do adaptations or in other media (movies/tv/radio), or do sequels based on those tales without needing the permission of the Conan Doyle estate, or have to pay royalties to the estate.
However, the stories written between 1924 and 1927 are still under copyright protection, and if they are reprinted or story elements or characters unique to those tales are used in new stories or movie/tv/audio versions, then the users do have to pay the Conan Doyle estate for use of the material.
That's the decision handed down by US District Court Judge Ruben Castillio in a Chicago courtroom this week when Chi-town author Leslie Klinger won his case against the Conan Doyle estate which was trying to stop publication of an annotated edition of new Holmes stories based on the public domain tales. (BTW, the reason the suit was filed here and not in New York or Los Angeles was that both Klinger and Jon Lellenberg, the American agent for the Conan Doyle estate, are based in Illinois.)
Considering that there are currently two tv series updating the character to the present, as well as a popular film series starring Robert Downey Jr as Holmes, who knows how many more versions will pop up in the near future?