US copyrights at the time these Holmes stories were published were good for 2 28-year terms, with a required renewal to get the second one. The Copyright Act of

US copyrights at the time these Holmes stories were published were good for 2 28-year terms, with a required renewal to get the second one. The Copyright Act of 1976 changed the term to "life of the author plus 50 years," but only for works created in 1978 or later. For works from before 1978 still in copyright under the old system, it extended the renewal term's length by 19 years for a new total of 75 years. The US thereafter had no works enter the public domain until 1998, with the oldest works that were still covered at the '76 Act's date of effectiveness (those from 1922) having finally expired 20 years later (copyrights always run through the end of the calendar year they expire in). Later that year, Congress tacked another 20 years onto all future and still-active existing copyrights with the Copyright Term Extension Act, so the public domain "paused" again until 2019, when works from 1923 entered the public domain. There have been no more extensions, so the following years have continued moving forward with successive years' works losing copyright protection. In 2023 the relevant year will be 1927. The final Holmes stories at issue here are from 1927, and so will be public-domain on January 1. It will be quite some time before anything under the "life of the author" regime in the US will fall into the public domain: authors who published works and then also died in 1978 would have the soonest expiration, in 2049.