Today the US Court of Appeals for the 7th Circuit issued its decision in Leslie Klinger v Conan Doyle Estate, in which upheld the decision of the US District Court for the Northern District of Illinois - Eastern Division that Mr Klinger was free to use material in the 50 Sherlock Holmes stories and novels that are no longer protected by copyright. Writing on behalf of the Court, Circuit Judge Richard Posner recalled the decision in Silverman v CBS, in which the 2nd Circuit held that when a story falls into the public domain also its story elements - including its characters - do. Works derived from earlier works whose copyright has expired may nonetheless be protected, but copyright will only extend to the "incremental additions of originality contributed by the authors of the derivative works."
Much more from Eleonora on the IPKat here
Background here http://the1709blog.blogspot.co.uk/2013/12/the-return-of-sherlock-holmes.html and here http://the1709blog.blogspot.co.uk/2013/09/the-expiring-detectives-last-case.html and here http://the1709blog.blogspot.co.uk/2013/03/sherlock-holmes-and-case-of-copyright.html