Copyright is a protection mechanism that is normally associated with the written word, although it extends to both published and unpublished literary and artistic works. The object covered by copyright must be in a tangible form such as text. You can't cover, for example, a dance as such, although you could write down the dance movements and copyright that. Copyright covers printed material, but it also extends to versions of the material that are stored on bard disk in a computer.

Copyright law varies from country to country and the precise rules depend on the local situation. However, in general, copyright grants the owner the right to his or own work including the exclusive right to produce derivative works or to distribute or display the work publicly.  In the USA, copyright extends for 70 years.

Don't think that just because you have the copyright of a work of art that you can actually distribute it. An author may write a book and own its copyright. But, when the author publishes the book, the author agrees to not to compete with the work being distributed by the publisher. If the author then reuses the material which is permitted under copyright law, the publisher can sue the author for breach of contract.

Copyright protection is quite remarkable because it is automatic and begins as soon as you create the work in a tangible form.

You do not have copyright to a work if you are employed by someone to create it; for example, a technical writer employed to write a manual for a microprocessor dose not own the copyright. Similarly, if you are commissioned to produce, say, a test for university students, you do not own the test.

You can't copyright ideas, procedures or designs which means that algorithms (software) cannot be copyrighted. Protecting the intellectual property rights of the software you develop has always been difficult. It seems that patent protection offers advantages over attempts to use the copyright law because new case law is developing as software is patented. Moreover, copyright will not protect your software against those who develop software independently (i.e., by constructing it themselves rather than by copying it).

Copyright protection can be strengthened by attaching a notice of copyright to the published work (assuming it is in written form) of the from

© 2004 joe smith

where the copyright symbol, ©, indicates a notice of copyright, the date indicates the years it was first published, and the name indicates the copyright owner. Since, 1989 (in the USA) a copyright notice is no longer required to claim copyright.

Copyright registration allows you to publicly register copyright; for example, in the USA you can register a work with the Library of Congress. Although registration is not required to obtain copyright, you need it if you are to file a suit against someone who has infringed your copyright.

Fair Use

There are circumstances when you can use copyrighted material without the owner's consent; for example, you may wish to quote an author when writing a review. Such a quotation is permitted and is called "fair use"; this is particularly true where the use of copyrighted material is for the benefit of the public in teaching, criticism, or research.  However, there are no precise rules governing what constitutes fair use and, therefore, you may have to test your assumption of fair use in court if the copyright holder decides to sue you. A copyright holder would probably have a better chance of succeeding in a case involving fair use of he or she could demonstrate that they had suffered financially because of the "fair use".

Full details on US copyright can be obtained from http://www.copyright.gov/circs/circ1.html