It's in the Constitution!
In 1787, the framers of the Constitution gave Congress the power to "promote the progress of science and useful arts by securing for limited times to authors and inventors the exclusive rights to their respective writings and discoveries" – Article 1, Section 3, Clause 8.
The copyright clause in the Constitution supports three principles:
Copyright Act of 1976
The Copyright Act of 1976 is the current federal law that outlines the protections given to original works. It also outlines the circumstances in which exemptions can be applied to ensure that progress of human knowledge is not hampered unnecessarily. Basic copyright protection provided by the Copyright Act of 1976 has changed very little since 1976.
The Copyright Uproar
The current uproar about copyright is a direct result of the ease of distribution that the digital media and the Internet have made possible. The Internet has not changed the law, just made it much more important to be savvy about copyright. Emails redistributing copyrighted materials, images downloaded from the Internet and incorporated into lectures, tests, and presentations to be delivered digitally, and inexpensive duplication and the power of student computing have created an environment where it is easy to do a great deal of harm without much effort.
Think about how difficult it used to be to share one printed copy of a book on reserve or to distribute copies of articles and images to a class. It was much more difficult (though certainly not impossible) to abuse an author's copyright when distribution was limited to paper. Now, digital communication has created an environment where distribution of copyrighted materials can zigzag across the country and the world more quickly than we used to walk to the photocopier.
Several acts have been passed in the intervening years to address copyright in a digital world, and they will be covered in this discussion as they apply. However, it's important to understand basic copyright first.