This document discusses copyright duration under the 1909 and 1976 Copyright Acts in the United States. It provides details on:
1) How copyright duration is determined based on when a work was created and published, and whether it falls under the 1909 or 1976 Acts.
2) The key aspects of copyright duration under the 1909 Act, including an initial 28 year term, 28 year renewal term, and requirements around publication and renewal.
3) How the 1976 Act extended copyright duration to the life of the author plus 50 years (later increased to 70) and eliminated renewal, but grandfathered in works published before 1978 under prior rules.