Click to listen to Johnny Cash's "Get Rhythm"

Even as a young turk, Johnny Cash sang with the voice of experience. The first disc of this fantastic two-CD set (which features 26 cuts previously unreleased in the U.S.) gives us the sound of Cash in his twenties – demos and radio appearances from the 1950s. Cash's singing is higher and sprier than in his prime, but the gravitas is there. (Check out the demo of a little ditty called "I Walk the Line.") Disc Two turns to outtakes and rarities from the 1960s. There are jailhouse weepers, lullabies and gallows humor like "Five Minutes to Live" – a jaw-dropping testament to the depth of the man's songbook.

Photos: Intimate, All-Access Shots of Johnny Cash

“Is It True”

As the British Invasion reached its peak in 1964, Brenda Lee went from Nashville to London to record one of her hardest-rocking hits, her perky vocal backed by a stuttering, squalling guitar. That guitar was played by session musician Jimmy Page, yet to skyrocket to fame with first the Yardbirds and then Led Zeppelin. "She said to me, 'I've come here to make a record with the British sound,'" remembered producer Mickie Most. "She felt she wouldn't get the same sound in Nashville because they're only just catching up on the British beat group sound of about six months ago."