Anyone have good book / article recommendation for procedural generation of background music? (No vocals, just instruments).

I'm not interested in:

How do I generate the sound of a particular note on a particular instrument

I'm interested in:

How do I generate the melody / score for the music.

Thanks!

EDIT:

Thanks for the reference to Brian Eno. I'm definitely looking into the ambient/user can ignore type of music. I.e. think the background music of a game. It's there to provide some basic mood, but the focus is the game.