Sherlock Holmes faces his greatest challenge — since his fight to the death with Professor James Moriarty at Reichenbach Falls. Who owns Sherlock Holmes, the world’s greatest detective? Is it the estate of Sir Arthur Conan Doyle? Or the mysterious socialite Andrea Plunket? Or does Sherlock Holmes belong to the public? This is the question currently being debated in copyright litigation in the United States courts, raising larger questions about copyright law and the public domain, the ownership of literary characters, and the role of sequels, adaptations, and mash-ups. Sherlock Holmes is a fictional detective first created by Conan Doyle for the 1887 novel A Study in Scarlet. Conan Doyle went onto publish a total of four novels and 56 Sherlock Holmes stories. And the Sherlock Holmes canon includes characters such as Dr John Watson, the Scotland Yard inspector Lestrade, Irene Adler, and Professor James Moriarty, the deviously evil and unhinged academic. Such is his popularity, Sherlock Holmes has been the subject of a number of sequels, adaptations, and imitations. And there has been a revival of Sherlock Holmes in modern times. There’s the BBC series Sherlock, starring Benedict Cumberbatch and Martin Freeman. There’s also a rival series called Elementary – set in the United States, featuring Lucy Liu as Dr Joan Watson. There’s even been a dispute between the two series. And there’s that rip-roaring movie franchise about Sherlock Holmes, directed by Guy Ritchie, starring Robert Downey Junior, with Jude Law as his trusty assistant, Dr Watson. Sherlock, the BBC version. Scholars Megan Richardson and David Tan have observed that, for a long time, sequels to Sherlock Holmes were tolerated by the author and his estate. But there’s also been concern with how the estate of Sir Arthur Conan Doyle has sought to manage the ownership and licensing of intellectual property rights associated with Sherlock Holmes. And this boiled over in 2013, with copyright litigation between an editor and the estate of Conan Doyle.