Johnny Cash's new boxed set, Cash Unearthed, is released today. The five-CD collection features 79 tracks, with 64 unreleased songs. Included in the new songs are duets Johnny did with Willie Nelson, Carl Perkins, Joe Strummer of rock band The Clash and Fiona Apple. Unearthed also contains a booklet with one of Johnny's last interviews. Johnny's children Rosanne Cash and John Carter Cash, along with Tom Petty, also contribute comments. In addition, there's a track-by-track discussion of each song.