What is copyright?

Title 17 of the United States Code defines copyright as a law meant to protect "original works of authorship fixed in a tangible medium of expression." This protection is for a limited time, and includes the right to publish and sell literary, artistic, or musical work. Originally copyright was meant to be a means by which government could restrict printing, but in the modern sense it protects authors, publisher, producers, and the public by ensuring the rights of the copyright holder to be credited for the work, to determine its use, and to benefit from it financially. Most countries have some sort of copyright law, and while there are differences, many countries have attempted to standardize it by entering international copyright agreements.

What does copyright protect?

United States copyright protection applies to "original works of authorship," including those that are:

• literary
• musical 
• dramatic 
• choreographic
• pictorial, graphic, and sculptural
• audiovisual 
• sound recordings
• architectural 

What is NOT protected by copyright?

United States copyright protection does not apply to works that are:

• not fixed in a tangible form (for example, an improvised performance that is not recorded)
• names, titles, short phrases, slogans, mere listings of ingredients or contents, familiar symbols or designs, mere variations of typography, coloring or lettering
• ideas, procedures, methods, systems, processes, concepts, principles, discoveries, or devices, as distinguished from a description, explanation, or illustration
• consisting entirely of information that is common property and containing no original authorship (for example: standard calendars, height and weight charts, tape measures and rulers, and lists or tables taken from public documents or other common sources)
• produced by the U.S. Government (see note)

From "Copyright Basics." U.S. Copyright Office Circular 1.

Note that while U.S. federal documents are generally not protected by copyright, state and local governments may, and often do, claim copyright on their publications. The same is true of many foreign governments.