Copyright protections last a long time; in fact, these rights even extend well beyond the life of the original creator. Identifying whether or not something falls within the scope of copyright law can be complex, but a few basic rules offer a good starting point:
Cornell University's Peter Hirtle has created a widely cited chart as a guide to determining whether or not a work remains in copyright:
Many works that ordinarily fall within the scope of copyrightable media--books, music, images, correspondence, etc.--are actually part of a vast collection of resources known as the public domain. Works in the public domain are not protected by copyright law and can be used freely for both noncommercial and commercial purposes.
The public domain in the United States includes:
For more information, we suggest "Welcome to the Public Domain," an overview authored by copyright expert Richard Stim and re-published by the Stanford University Copyright and Fair Use Center.