A record can't hold much music. A full 80 minute CD takes 2 records. A record can hold about 45-50 minutes without quality being lost. Any more information over the 45-50 minutes put on a record, the lower the sound quality is. This is one of the reasons "Leave Me Alone" is not on the vinyl or cassette. This is also why "Billie Jean" & "The Lady In My Life" were shortened and why old albums are short compared to today. If you notice, on the 2001 remasters, on "Off The Wall, Thriller, and Bad extra material was added, but on "Dangerous" (which filled up the entire CD), there's no extra stuff. On the Motown albums re-releases, they put 2 albums on 1 CD, plus 1 or 2 extra songs.