The sixth and final volume of Johnny Cash's 'American' series, 'American VI: Ain't No Grave,' was officially issued on Feb. 26, the day that would have been the late country legend's 78th birthday. The album marks some of Johnny's last recordings and includes cover songs such as Sheryl Crow's 'Redemption Day,' Kris Kristofferson's 'For the Good Times,' and Hawaiian queen Lili'uokalani's 'Aloha Oe' (whose title means 'Farewell to Thee'). But among the covers is one of the last songs that Johnny Cash wrote, a weighty spiritual with a biblical theme, titled after its source, 'I Corinthians: 15:55.'

"As far as his serious work, it was his last great song," Johnny's son John Carter Cash tells The Boot. "He wrote 'Like the 309,' which was on 'American V,' after he wrote 'Corinthians,' but it was one of the very final songs he wrote. He'd been working on this idea for years. 'Oh death where is thy sting'," he quotes solemnly. "That's the main catch line in the song, which is a scripture. Straight from the apostle Paul. That's a pretty powerful line. Shakespeare used it."

John Carter worked alongside his father as associate producer on the final four albums in the 'American' series, a passionate set of sometimes-surprising cover songs, all of which were produced by Rick Rubin (Dixie Chicks, Red Hot Chili Peppers). "Which basically means I facilitated when Rick wasn't there," he says humbly. "My father continued to record whether or not Rick was in Nashville. He was in the studio on a regular basis, recording song after song up until his passing. He would call me and say, 'Let's go in the studio,' and I'd call up the musicians."

The 'American Recordings' series began the series in 1993, recorded in Los Angeles and at Johnny's cabin studio in Hendersonville, Tenn. John Carter, now 40, recalls those cherished final sessions in 2003 before his father's passing in September. "He wrote during the summer. He was writing in August I know."

'American VI: Ain't No Grave's' strong spiritual theme was a deliberate choice, says John Carter. "I think my father would have every single one of them be the focused on spiritually, all these 'American' records, in one form or fashion. Spirituality is the driving theme of the record and there's a happy, laughing goodbye at the end of it with 'Aloha Oe'."

John Carter says there are still many unreleased tracks that could see the light of day. "There is a good bit more. I have a feeling there won't be another 'American' series record, as far as a ten-song CD. There is enough for another box set of unreleased material. But I don't know what the plan is for that. But as far as the most beautiful recordings that were gleaned from it, they are here on 'American VI'."