According to Hirtle (2018), works published in the United States or countries with copyright agreements with the U.S., copyright protection extends 70 years after the death of the creator or 95 years after publication if the creator is a corporation. There are, however, numerous nuances. What about, for example, a work published in the U.S. within 30 days after being published abroad between 1923 and 1977? For this and other fun copyright facts, see the Hirtle’s (2018) website at Cornell (See References Cited Section).
In A Brief Introduction and History, the United States Copyright Office states:
It [copyright] is a principle of American law that an author of a work may reap the fruits of his or her intellectual creativity for a limited period of time. Copyright is a form of protection provided by the laws of the United States for original works of authorship, including literary, dramatic, musical, architectural, cartographic, choreographic, pantomimic, pictorial, graphic, sculptural, and audiovisual creations. Copyright literally means the right to copy. The term has come to mean that body of exclusive rights granted by law to authors for protection of their work. The owner of copyright has the exclusive right to reproduce, distribute, and, in the case of certain works, publicly perform or display the work; to prepare derivative works; in the case of sound recordings, to perform the work publicly by means of a digital audio transmission; or to license others to engage in the same acts under specific terms and conditions. Copyright protection does not extend to any idea, procedure, process, slogan, principle, or discovery.
In Copyright in General, the United States Copyright Office suggests we ask these questions to understand copyright:
What is copyright? Copyright is a form of protection grounded in the U.S. Constitution and granted by law for original works of authorship fixed in a tangible medium of expression. Copyright covers both published and unpublished works.
What does copyright protect? Copyright, a form of intellectual property law, protects original works of authorship including literary, dramatic, musical, and artistic works, such as poetry, novels, movies, songs, computer software, and architecture. Copyright does not protect facts, ideas, systems, or methods of operation, although it may protect the way these things are expressed.
Do I have to register with your office to be protected? No. In general, registration is voluntary. Copyright exists from the moment the work is created. You will have to register, however, if you wish to bring a lawsuit for infringement of a U.S. work.
Why should I register my work if copyright protection is automatic?
Registration is recommended for a number of reasons. Many choose to register their works because they wish to have the facts of their copyright on the public record and have a certificate of registration. Registered works may be eligible for statutory damages and attorney's fees in successful litigation. Finally, if registration occurs within five years of publication, it is considered prima facie evidence in a court of law.
[Note: Prima facie evidence is “evidence that will establish a fact or sustain a judgment unless contradictory evidence is produced” (Garner, 1999, p. 579).]