For Sherlock Holmes Fans - including thos who ever imagined other stories or mysteries from his adventures - the author's books enter the public domain in January 2023!
While most of Sir Arthur Conan Doyle's stories are in the public domain, ten of his stories were published in the 1920s, and while some of those stories have been entering the public domain since 2016, others remain under copyright until January 1st, 2023.