OS X 10.8 and later only. This applet checks your entire iTunes library for missing and presumed dead tracks--those tracks that iTunes is unable to associate with a file and which are listed in iTunes with a "!"--and can create a text file listing these tracks by last known File Path (if available), Song Name, Artist and Album, which you can view using TextEdit.
Also see Music Folder Files Not Added
To find and delete dead tracks see Super Remove Dead Tracks.
iTunes can't find the files pointed to by the Location property of these track entries.
Perhaps Also of Interest...
downloaded 1m 20s ago
Export artwork of selected tracks to parent or specified folder
downloaded 4m 6s ago
Set the Plays of selected tracks.
downloaded 10m 12s ago
Put file creation date to each track's comment tag
downloaded 11m 27s ago
Applet assists with swapping, copying, appending data between track tags
downloaded 13m 17s ago
Create a Ringtone track from a selected track
downloaded 15m 25s ago
Exports and then re-imports selected tracks' artwork