What is Public Domain?
Copyright does not last forever. When works stop being protected by copyright, they fall into the "public domain." A work in the public domain may be freely copied by anyone.
What makes something public domain? That's a tricky question! It all depends on when the work was created and if/when the creator has died.
Below are some resources which will give you more information on public domain.
Websites:
Copyright Term and the Public Domain in the United States
http://www.copyright.cornell.edu/training/Hirtle_Public_Domain.htmHow to Determine Whether a Work is in the Public Domain
http://www.public.asu.edu/~dkarjala/publicdomain/SearchC-R.htmlNew Rules For Using Public Domain Materials
http://copylaw.com/new_articles/PublicDomain.html
Books:
Search URSUS by KEYWORD for copyright.
UMF Staff:
Janet Brackett, Head of Access Services at the Mantor Library, is very knowledgeable about copyright issues and can help to guide you in these matters.