When may copyrighted materials be copied or otherwise used without the copyright owner’s permission?
The Copyright Act grants copyright owners certain exclusive rights with respect to their work. These include the rights to reproduce the work, prepare derivative works based on the work, distribute copies of the work to the public, and perform and display the work publicly. If you intend to exercise any of these rights with respect to a copyrighted work, you must obtain the owner’s permission to do so. The copyright office of the Library of Congress prints a very helpful circular (PDF) about copyright law (PDF).
Your use of copyrighted work may be permissible if it constitutes "fair use," if it falls within the "Safe Harbor Guidelines," or if it meets the Rules of Thumb. If you are still in doubt about your use of the materials after reviewing these sections of the website, feel free to contact the Fair Use Committee.