Fifty Sherlock Holmes works published before 1923 by Arthur Conan Doyle are in the public domain, a US appeal court ruled, and others may refer to them freely without paying licensing fees to the Scottish writer's estate.
The court in Chicago said on Monday that US copyright law did not cover earlier works depicting the brilliant detective, including references to Holmes, his sidekick Dr Watson, his arch-enemy Professor Moriarty, 221B Baker Street, and even Holmes' cocaine use.
Writing for a three-judge panel, Circuit Judge Richard Posner said that there was no basis to extend US copyrights beyond their expiration.
He said only Conan Doyle's last 10 Holmes works, which were published between 1923 and 1927 and have copyrights expiring after 95 years, deserved protection. Conan Doyle died in 1930.
"When a story falls into the public domain, story elements - including characters covered by the expired copyright - become fair game for follow-on authors," Posner wrote.
To rule for the estate, he said, would encourage authors to write more stories with old characters. "The effect would be to discourage creativity," he wrote.
The decision was a victory for Leslie Klinger, editor of The New Annotated Sherlock Holmes and other Holmes books.
Klinger had paid the estate a US$5,000 licensing fee for a prior work but sued after refusing to pay another fee for a compendium of new Holmes stories that he and co-editor Laurie King were editing, In the Company of Sherlock Holmes.
Their publisher Pegasus Books refused to publish the work after the Conan Doyle estate threatened to stop sales by Amazon.com and Barnes & Noble unless it received another fee.
Monday's decision upheld a December 2013 ruling that was made by US District Judge Rubén Castillo in Chicago.
"I am very, very pleased," Klinger said in an interview. "The urge to publish more comes from the love for the first 60 stories, and people should be encouraged to create more."
He said he hoped to publish the compendium in November.
Benjamin Allison, a lawyer for the Conan Doyle estate, said no decision had been made on an appeal and that it remained to be seen how Klinger and others could use the author's characters without using the "full expression" of those characters.
The last 10 Holmes works introduced such details as Watson's second wife and Holmes' retirement from his detective agency.
"Many aspects of Holmes' character, such as his growing friendship with Watson and his human warmth, were created in the last 10 stories and remain protected by copyright," Allison said in an interview.
Jonathan Kirsch, a lawyer for Klinger, said he was gratified by the decision. "Copyright begins and ends, and cannot be extended indefinitely," he said in an interview.