Reader Joe Feil would like to know more about how the music in his iTunes library is parsed out to his playlists. He writes:
Can you tell me how to find which playlists contain a certain song title? I can easily search for a song title, but it doesn’t show where (in which playlists) that title is located. I sometimes want to eliminate duplicate titles or play those containing certain songs.
In recent versions of iTunes, Control-click on a track and, from the contextual menu that appears, select Playlists. Within that Playlists submenu you’ll see all the playlists that track belongs to.
You can use a smart playlist to help you locate songs that appear in multiple playlists. For example, this smart playlist:

will hold the titles of tracks that appear in three playlists.