Copyright as defined by the United States Copyright Office "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 Copyright covers both published and unpublished works."
Below are examples of works protected under copyright law:
Copyright owners have the following rights:
This right also applies to the individual images of a motion picture or other audiovisual work. Perform the work publicly by means of a digital transmission if the work is a sound recording. Copyright also provides the owner of copyright the right to authorize others to exercise these exclusive rights, subject to certain statutory limitations.
Works not copyrighted include:
For legal issues you can search Westlaw Database.
The Duration of a copyright varies depending on the creation date of the work or multiple authors.
A work of authorship is in the "public domain" if it is no longer under copyright protection or if it failed to meet the requirements for copyright protection. Works in the public domain may be used freely without the permission of the former copyright owner.
For more details regarding the term of a work, visit the Cornell University's chart on Copyright Term and the Public Domain in the United States.