The Libraries sidebar holds and organizes the libraries and events that contain your imported media (video, audio, and still images) and your projects. When you select an event or a library in the Libraries sidebar, its clips and projects appear in the browser. The Libraries sidebar also contains Keyword Collections and Smart Collections, which provide a powerful way to organize your media using keywords and saved searches.
To show or hide the Libraries sidebar, do one of the following:
Click the Libraries button in the top-left corner of the Final Cut Pro window.
Choose Window > Go To > Libraries (or press Command-1).