Copyright laws are laws that protect an original author from other people stealing their work.  Copyright laws protect everything from books and inventions to ideas. Violating copyright laws is a crime.  It is important to have permission from the author or to give credit to the author if you want to share their work.

Fair Use allows copyrighted material to be used with limited measures.  This means that you do not have to have permission to use the work, but you are limited to how much you can use, where you use it, and what you use it for.