It's been four years since Johnny Cash passed away at the age of 71, but treasures from one of music's most towering figures have slowly and steadily trickled from his vaults. Earlier this month brought the release of Vivian Cash's 'I Walked the Line: My Life With Johnny Cash,' a memoir written mostly with Johnny's words, culled from letters he wrote to Vivian -- his first wife -- while the two young lovers were separated as Johnny served in the United States Air Force in Germany from 1951 to 1954. While nearing the end of his time abroad, a then-obscure 22-year-old Johnny made a 78 recording for Vivian, featuring a tender spoken-word declaration of his love on one side, and on the other, a performance of 'Darlin' Am I the One?' -- originally performed by Carl Smith, a country singer who was married to June Carter, who would become Johnny's second wife. The recording has never been made public -- until now.