You can learn more about copyright at the Copyright Office Web site. A good place to start is with the Frequently Asked Questions, which will lead you to the proper forms to use to register your copyright, tell you what copyright protects and provide information on the mandatory deposit requirement. Information is also available in Spanish at http://www.copyright.gov/espanol/

Was there copyright in the United States before 1870?

Yes, but it was administered by the Clerks of the U.S. District Courts. Upon enactment of the 1870 law, all original records of copyright maintained in the 41 states and territories (estimated to cover approximately 150,000 registrations) were turned over to the Library of Congress for safekeeping. These historic volumes are now preserved in the Rare Book and Special Collections Division, along with many accompanying title page deposits. Entries for great literary classics such as The Raven, The House of the Seven Gables and Uncle Toms Cabin can be found in these records. A Brief History and Overview of the Copyright Office describes the mission of the office, its services and how it supports the U.S. Congress and the nation.