For the working musician, having just a rudimentary knowledge of copyright law can be as valuable to your career as knowing your barre chords.

Also, and on a more practical level, knowing what you have and what you don't have can greatly facilitate your music business dealings, whether with a producer, a label, a music publisher, or your bandmates.

 http://beatblog.typepad.com/melon/2007/05/music_biz_incom.html