For works created after 1977, copyright in the United States lasts for the life of the author plus an additional 70 years. For works of joint authorship, the copyright last until 70 years after the death of the last surviving author.
For anonymously created works and works made for hire (that is, created for an employer) copyright lasts for 95 years from publication or 120 years from creation , whichever expires first.
Determining whether works created before 1978 are still protected by copyright can be a complex undertaking.
For works first published in the United States, or by US citizen or nationals, copyright lasts for 95 years from publication. But depending upon when a work was created, it is subject to different requirements regarding copyright notice, registration, and renewal. For example, before 1978 U.S. law required that works be published with a notice of copyright to receive protection. Failure to comply with this requirement would result in the work being in the public domain. Works works published before 1964 were required to be registered and have their copyright renewed after 28 years.
The Copyright Term and the Public Domain, a guide to copyright duration originally created by Peter Hirtle and currently maintained by Cornell University Libraries, is a useful resource for starting to research a work's copyright status.
One example of the complexity of determining if something is in the public domain come from Peter Hirtle; the possibility that the oldest work still under copyright may be a 1755 letter from John Adams to Nathan Webb. It was not published until 1956, so its copyright won’t expire until 2052 – almost 300 years after its creation! You can read Peter's initial posting and subsequent follow ups on the librarylaw blog.
Many if not most works published outside the United States failed to comply with the required formalities of the 1909 copyright act, to secure copyright in the United States, and therefore fell into the Public Domain. However in 1996 Under the General Agreement on Tariffs and Trade (GATT), particularly through the Uruguay Round Agreements Act (URAA), the United States restored copyright protection to certain foreign works that had previously fallen into the public domain in the US due to non-compliance with US formalities, effectively giving copyright protection to these works again, primarily effective on January 1, 1996, for eligible countries that were members of the WTO (World Trade Organization) or Berne Convention at that time; this process is known as "copyright restoration" for foreign works under GATT and are protected for 95 years from publication.
To be eligible for GATT Restoration:
