In a ruling Monday, an appeals court affirmed a December 23 ruling in which Illinois federal judge Ruben Castillo declared that the character of Sherlock Holmes, as well as other characters and elements of Sir Arthur Conan Doyle’s iconic mystery series published before 1923, is in the public domain.

The basic cut-off date for the public domain in the U.S. is generally considered to be 1923. In a declarative judgment, Castillo held that for all but a few remaining stories, the public "may use the pre-1923 story elements without seeking a license."

Writing for a three-judge panel of the Seventh Circuit, Judge Richard Posner affirmed Castillo's ruling. Posner wrote: “We cannot find any basis in statute or case law for extending a copyright beyond its expiration. When a story falls into the public domain, story elements, including characters covered by the expired copyright become fair game for follow-on authors.”

The federal suit was brought in early 2013 by author and scholar Leslie Klinger. Klinger, who is also an attorney, told PW that the suit became necessary after the Doyle estate attempted to extract a license fee for a new book he was co-editing, In the Company of Sherlock Holmes (Pegasus Books) with author Laurie R. King, the bestselling author of the "Mary Russell" series of mysteries that also feature Sherlock Holmes.

The decision excludes roughly 10 of Conan Doyle’s Holmes stories, which remain under U.S. copyright protection, and which Klinger had excluded from his suit. But roughly 50 other stories featuring the famous characters are now officially in the American public domain.