Cornell Notes is a note-taking system that structures notes into three columns: a cue column on the left, a notes column in the middle, and a summary/questions column on the right. The cue column contains keywords, questions, and main ideas. The notes column is where the main content is written down. The summary/questions column is used to review notes by writing summaries, questions, or important points. The document provides examples of what to write in each column and tips for taking faster notes such as abbreviating words and using bullets.