What is copyright?

Legal protection for original works, granted to the authors/creators of the original works.
The author/creator is the only person who can grant permission to copy, distribute, display, perform or make "derivative works" (translations in language, format or medium) of the original.
History of Copyright Law (6 minutes)
Copyright Basics from the US Copyright Office (12 page PDF)
Reproduction of Copyrighted Works by Educators from the US Copyright Office (24 page PDF)

Copyright can be eroded in three ways:

  • Public Domain: After a certain amount of time, copyright protection ends, and the work is 100% freely usable.
  • Creative Commons: The author alters the copyright by purposefully giving away certain rights (like distribution), but may retain other rights (like attribution or commercial use).
  • Fair Use: Based on 4 criteria, any use of a copyrighted work may be considered "fair use," and allowed.

Public Domain

Works that have lost their copyright or are ineligible for copyright are in the public domain, and they may be freely used by anyone, for any purpose.
While there are many laws and stipulations about when a work enters the public domain, in general works published before 1923 are in the public domain. For a concise overview, see Stanford University Copyright and Fair Use, and for a lengthier and more detailed breakdown please see Cornell University.

Creative Commons

Creative Commons is an alternative to traditional copyright; it allows authors to allow their works to be used in some ways and for some purposes, but still provides some protection for the author's intellectual property.
For instance, a person may allow their works to be freely distributed, but only for non-commercial uses.
Creative Commons: An Alternative to Copyright
For more information on Creative Commons, please see Creative Commons.

Fair Use

Fair use is a section of copyright law that specifically allows use of copyrighted material without the author's permission, based on 4 basic criteria.
  • The purpose and character of the use (criticism, parody, education, review, etc.)
  • The nature of the original work (factual information vs. original ideas, previously published vs. unpublished)
  • The amount of the original work used (whole, small part, etc.)
  • The effect the use will have on the potential market or value of the original.
There are no specific rules, amounts, or other prescriptive criteria that will automatically denote "fair use" or "copyright infringement."
For more on this topic, see The US Copyright Office, Stanford University Copyright and Fair Use,Fair Use Checklist.