"At midnight on New Year’s Eve, all works first published in the United States in 1923 will enter the public domain. It has been 21 years since the last mass expiration of copyright in the U.S. …
…Much the same will happen every January 1 until 2073, revealing long-overlooked works from the Harlem Renaissance, the Great Depression, World War II and beyond. (After 2073, works published by authors who died seven decades earlier will expire each year.) “We’re going to open these time capsules on a yearly basis…and potentially have our understanding of that year and all the contents change,” said Paul Saint-Amour, a professor of English at the University of Pennsylvania and editor of Modernism and Copyright."
https://www.smithsonianmag.com/arts-culture/first-time-20-years-copyrighted-works-enter-public-domain-180971016