This document summarizes copyright law as it relates to public domain works, materials on the internet, fair use, and getting permission to use copyrighted works. It discusses how old copyright laws led to overprotection and challenges around mass digitization of works. The Teach Act is summarized as expanding the rights of educators to use copyrighted works under certain limitations and conditions. Fair use is described as allowing limited use of copyrighted works for purposes like teaching without permission, based on a four factor test. The document also provides references for further information.