Are P2P networks illegal?

Sharing work or media through a peer-to-peer (P2P) network is legal if you own the copyright, thus you own the right to determine if and how that work is distributed. For example, you can write and produce an original song and make it available for others to download for free through a P2P file sharing program. However, it is illegal for you to download or share copyrighted works without permission from the copyright owner.