What a year it was for Anglo-American literature and the arts!
1925 was the year of heralded novels by F. Scott Fitzgerald and Virginia Woolf, seminal works by Sinclair Lewis, Franz Kafka, Gertrude Stein, Agatha Christie, Theodore Dreiser, Edith Wharton, Aldous Huxley ... and a banner year for musicians, too. Bessie Smith, Ma Rainey, the Gershwins, Duke Ellington and Fats Waller, among hundreds of others, made important recordings. And 1925 marked the release of canonical movies from silent film comedians Buster Keaton and Harold Lloyd.
As of today, every single one of those works has entered the public domain. "That means that copyright has expired," explains Jennifer Jenkins, a law professor at Duke University who directs its Center for the Study of the Public Domain. "And all of the works are free for anyone to use, reuse, build upon for anyone—without paying a fee."
On January 1 every year, a new batch of published works is liberated from the constraints of copyright. (For a long time, copyright expired after 75 years, but in 1998, Congress extended the date of copyright expiration for works published between 1923 and 1977 to 95 years.) It's difficult to overstate the importance of having work in the public domain. For example, can you imagine the holidays without It's A Wonderful Life? That movie happened to be unprotected by copyright, so it was able to be shown—a lot—for free, contributing to its establishment as an American Christmas classic.
It also means books can be published more cheaply and made available for free online; that old "orphan" films can be preserved by archivists; that scholars can access and publish material more easily; that musicians can sample and experiment with the songs of an earlier generation and that classic characters can be given new life and new interpretations.