This document discusses Creative Commons licenses, including what they are, how they work, and how to use them. Creative Commons licenses provide alternatives to traditional copyright that allow for some uses while still protecting author rights. They use a three-layer system including legal code, human-readable explanations, and machine-readable tags. The most common licenses are CC BY, which allows commercial use with attribution; CC BY-SA, which requires derivatives to use the same license; and CC BY-ND, which only allows sharing unchanged. Creative Commons licenses have been upheld in court and are a way for libraries to help users find and share open educational resources.