If not, how can he get them and will he have to pay money to get them back? Does anyone know how that works? Isn't that important to own them, I mean, I know financially it is but I can't remember exactly why.

There is monetary value around owning the masters, yes. Though I think he still would get substantial money around royalties no matter who owned them

Unless I'm really dumb (which is always possible), I think Warners owns them.

This has been covered many times, including details in this recent thread:

http://www.prince.org/msg/7/209853

Prince most likely has legal ownership of the actual master recordings to his songs.

He has contractual obligations with Warner Brothers under which he has assigned the rights to use of the recordings. Those rights revert back to him 35 years after their original release.

Meanwhile, he continues to benefit financially from publishing monies from the recordings.

There are lots of articles on the web which explain how such rights generally operate, for example:

http://www.howstuffworks....ntract.htm

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[Edited 12/3/06 23:15pm]

Already covered here http://www.prince.org/msg/7/209853

And on that note