What laws govern copyrights?

Section 8 of Article I of the United States Constitution authorizes Congress to grant copyright rights (as well as patent rights) to authors for a limited time, allowing the authors to protect their works. Congress used this power to enact the Copyright Act, which exists as Title 17 of the United States Code. Prior to 1976, the Copyright Act did not offer any protection for unpublished works, and such protection was governed by state law. However, with the enactment of the 1976 Copyright Act, which amended Title 17 of the United States Code, unpublished works are now protected under the federal copyright statutes. The only major provision of state law relevant to copyright law is for works which are not fixed (such as a live improvised performance which is not recorded) - in some instances, common law will offer protection to such work.