The story of American popular music contains several moments when a career that has gone south is dramatically resurrected before an awed and grateful public. Sometimes the moment is brief, such as Elvis’s appearance on NBC’s Christmastime special in 1968, or it can last for years, like the Dylan revival that began with Time Out of Mind and shows no sign of ebbing. Johnny Cash’s comeback, heralded by American Recordings and lasting for the final decade of his life, was even more unexpected than Elvis’s or Dylan’s. Cash had been dropped from the roster of Columbia Records and was playing gigs at North Dakota rodeos when he met rap producer Rick Rubin near the end of 1993. Although he knew very little about either Cash or country music, Rubin signed him to the fledgling American Recordings label. The partnership revitalized Cash, restoring his powers as an interpreter of country and pop, won several awards and brought the 1990s generation into his listenership.

After his death this past September, American Recordings released Cash Unearthed, a boxed set that gathers outtakes from Cash’s four studio albums with Rubin (American Recordings, Unchained, Solitary Man and The Man Comes Around), a disc of gospel hymns performed solo by Cash on acoustic guitar and a fifteen-song compilation titled Best of Cash on American. In keeping with the rest of his catalogue, the set contains songs of murder, faith, trains, the open road and lost love, by country forebears such as Jimmie Rodgers and the Carter Family as well as Beck, ex-grunge rocker Chris Cornell (of Soundgarden fame) and other “alternative” songwriters. It is a deep and often puzzling lexicon, with no peer in recent American music, and one that makes for a pleasantly coherent end to a wild and uneven career.

In the beginning, Rubin simplified the Cash sound, stripping it of the studio gimmickry and melodramatic production that marred most of his releases in the late 1970s and ’80s. Rubin told him: “You would take your guitar, sit down in front of a microphone and sing me the songs you love. Just sing me everything you want to record.” They recorded over a hundred songs at these first sessions. In that time Rubin also played Cash some of his favorite songs, by artists like Tom Waits and Glenn Danzig. Cash responded to this material eagerly–“song collecting is something I’ve always been interested in.” The songs on American Recordings revisit the dark and comic themes long associated with Cash, all drawn from sources that seem forbiddingly incongruent. The album’s success turned out to be a powerful statement on the genealogy of recorded music as much as a sign of Cash’s return to relevance and credibility.

The strange coupling of sources became a sort of trademark. On American IV: The Man Comes Around, the most memorable performances are of Nine Inch Nails’ “Hurt,” Depeche Mode’s “Personal Jesus,” a duet with Nick Cave on “I’m So Lonesome I Could Cry,” the Tin Pan Alley standard “We’ll Meet Again” and Cash’s own “The Man Comes Around” and “Tear Stained Letter.” It is clear that Rubin, who is best known for working with the Beastie Boys, Run DMC, Red Hot Chili Peppers and LL Cool J, had an agenda: to market Cash as the original outlaw rocker and, by extension, as one of the founding fathers of gangsta rap. But it is a tribute to Cash’s vocal power and natural musical talents that so many of these performances impart a convincing aura of originality. His lush, pliable baritone makes itself at home in both Soundgarden and Jimmie Rodgers. “Nobody’s song is safe out there from me,” Cash said. “I go through ’em all, picking and gleaning.” He reworks many of his own singles as well, from as far back as 1957’s “Give My Love to Rose,” and several tracks on Unearthed acknowledge Cash’s contemporaries–Nashville writers like Billy Joe Shaver and Kris Kristofferson, fellow Sun Records alumni Roy Orbison and Carl Perkins. There is a lovely nod to George Jones in a performance of “He Stopped Loving Her Today.” Listening to the eight discs Cash recorded for the American Recordings label, one is reminded of the great song-gathering projects of the last century, Plantation Songs, the Anthology of American Folk Music and so forth. Unearthed is an anthology in its own right, mostly of the postwar white American song literature, from Rodgers and Hammerstein to Dolly Parton to Neil Young.

After American Recordings, Tom Petty and the Heartbreakers became the house band for Cash, and they were complemented by superb musicians throughout: longtime Cash partners Jack Clement and Marty Stuart, bluegrass stalwarts Norman Blake and Randy Scruggs, and a number of guests, including Fiona Apple, Don Henley, Willie Nelson, Merle Haggard and the late Joe Strummer, who join Cash on vocals. Some moving duets were also made by Cash and his wife, June Carter. Without these recordings, it is likely that Cash’s career would have come to a quiet or ignominious end, the obituaries upon his death chronicling the loss of a great and precocious talent to a lifelong battle with drugs. His struggles with pills continued while he was working with Rubin, but the collaboration’s success, combined with his recurring health problems, mellowed his self-destructive habits, and he became more and more focused on honing his repertoire. The songs on American Recordings, above all, are about this paradox: Only at the behest of a modern rap icon did Cash properly return to his country and rockabilly roots. By looking at the end of the tradition, he was able to find the beginning.

Cash generally stopped writing memorable songs in 1958, when he left Sun Records for Columbia and entered a second year of addiction to amphetamines. Although he remained popular and prolific, producing an average of two or three albums a year, the fire that produced “Folsom Prison Blues,” “I Walk the Line,” “Big River” and other country classics burned too swiftly, too brightly and swallowed much of his creative talent in the backdraft. “Man in Black” aside, it is difficult to name a Cash standard written after the 1950s. On the American Recordings series, there are only eight new Cash originals (three of which appear in altered versions in the boxed set), and five of these date from the first record with Rubin. After Cash was found to have a nervous system disorder in 1997, his songwriting practically ended altogether.

Yet he somehow managed, in the last years of his life, to write what is arguably his greatest original song, “The Man Comes Around.” The song begins and ends by quoting from chapter six of the Book of Revelation, in which Saint John the Divine encounters the spirits of Hell and Death riding horseback. The music opens starkly, with staccato strumming of a single chord; a boom-chicka-boom vamp on C. Cash’s melody, too, is monotone, conjuring doom and portent by canceling any particular tonality. “There’s a man going around, taking names/And he decides who to free and who to blame.” Cash speaks these opening lines as much as he sings them; along with the reciting of Revelation, he may as well be delivering verse from a pulpit. Then he comes to a vision of Judgment Day, “there’ll be a golden ladder reaching down,” and the guitar breaks out of the vamp, moving into a major-chord progression that marvelously affirms the tag line “when the man comes around.” Rubin’s production is sharp, doubling the roots of the chords deep in the register of a piano and adding more guitars and an organ in the background to create a feeling of divine presence. The song eloquently gathers all of the contradictions Cash felt as a practicing Christian–wickedness, rebellion, the inevitability of sin in the face of a merciful and redeeming Father–and one line in the chorus, “one hundred million angels singing,” poignantly echoes the last words of Cash’s older brother Jack, whose death the singer called “more of an inspiration, I suppose, than anything else that has ever come to me through any man.”

No other American songwriter–certainly none of Cash’s immediate heirs or predecessors, like Hank Williams or Dylan–possessed the sort of obsession, or waged the same struggle, with faith inherent in a song like “The Man Comes Around.” Faith is what unites all of Cash’s best music. Even his most devilish murder songs, like “Delia’s Gone” or “Folsom Prison Blues,” are a kind of slap at God, another way of depicting his frustrated yearning for redemption. Much of Cash’s greatness is rooted in this sort of ambivalence; he said in one interview, “The battle against the dark one and the clinging to the right one is what my life is about.” The context surrounding this faith is clarified by the fourth volume of Unearthed, My Mother’s Hymn Book, a collection of fifteen tunes taken from a songbook owned by Cash’s mother, Heavenly Highway Hymns. Cash accompanies himself on guitar, turning traditional hand-clappers like “Do Lord” and “When the Roll Is Called Up Yonder” into subdued folk pieces. His singing is discernibly more soulful than it usually is; these songs come off as a cappella dirges sung alone in a cathedral. On “Softly and Tenderly,” for instance, he stretches his voice as high and as resonantly as its seventy years would allow, the lines “come home, come home, ye who are weary come home,” set forth as though he were finally auditioning before God’s ear.

The completion of this album was deeply satisfying to Cash–“you asked me to pick my favorite album I’ve ever made and this is it”–since there was no music closer to his heart (two of the hymns, “I’ll Fly Away” and “I’m Bound for the Promised Land,” were sung at Jack’s funeral). When he first met Sam Phillips of Sun Records, Cash said he wanted to record a gospel album. Phillips replied that gospel didn’t sell; Cash came back a few weeks later and sang “Hey, Porter” instead. In interviews over the years he would frequently return to the idea of recording a solo gospel album. He learned to love that music as a boy on the farm in Dyess, Arkansas. “The last thing I remember before going to sleep,” Cash wrote once, “was my mother beating time on the old Sears Roebuck guitar, singing ‘What Would You Give in Exchange for Your Soul?'” When John was 4, the Cashes sent away to Sears Roebuck again, this time for the radio on which he would discover Rodgers, Hank Snow and the Louvin Brothers’ noontime broadcast.

Heavenly Highway Hymns predates even this–“my mother’s guitar and singing was like the harp of King David that we read about in the Bible. It brought a closeness and comfort that couldn’t be found any other way…. By the time I was four I was singing along with her on the gospel songs.” It is easy to see why Cash saw this album as the central achievement of his collaboration with Rubin. Working his way down the line, from U2 through Neil Diamond and Chuck Berry and Alan Lomax to the Carter Family, he finally arrived at the earliest music of his childhood. Just months before he died, he recorded My Mother’s Hymn Book in his cabin studio, which from the outside doesn’t look all that different from the five-room farmhouse in which he grew up in Dyess. In the notes to Unearthed, Cash writes, “All my life I worked towards that end.” Past this, there were no more songs.