There's more to building an iTunes library than just collecting a lot of songs. If you want to have any control over which songs you listen to when, you must create and manage playlists. A playlist is a group of songs that you put together based on some kind of theme. The theme could be a favorite artist or group, your favorite oldies, or the songs that motivate you to work a little harder on the treadmill.
If you're like most people, you'll quickly build up a long list of playlists, with many songs in common. It's easy to lose track of which songs you've put on which playlists. To avoid duplicates, you can check a song and see which playlists it's already on. In your iTunes Music Library, right-click on a song's title and select 'Show in Playlist' from the pop-up menu. A submenu will pop out, showing all of the playlists the song belongs to.
