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

“Ambling Alp”

The "Ambling Alp" was the nickname of the six-and-a-half-foot-tall Primo Carnera. Though the song is named after the Italian-born 1930s heavyweight champion, Yeasayer are actually paying tribute to boxing legend Joe Louis with this first-person psychedelic dance-rock tune. “I was always interested in writing a song that had boxing mythology in it,” Yeasayer’s Chris Keating said. “It’s pretty fascinating: There were so many amazing characters, and it was so closely entwined with 20th century history.” Yeaseyer also invokes German champ Max Schmeling and hints at the historical significance placed on the historic bouts between the Nazi-era boxer and the African-American Louis.