Johnny Cash's massively important and prolific career had its fertile and fallow periods, but few expected a major peak in 1994, after years of forgettable albums, cultural invisibility, and poor sales. Fewer still expected a resurgence under the guidance of Rick Rubin, the producer best known for his legendary work in rap and heavy metal. But Rubin's initial vision for Cash–sitting him down with an esoteric assortment of source material and recording the singer's bare-bones interpretations–helped spark a career renewal that continued through Cash's death in September. American Recordings, the first fruit of their collaborations, ranks among Cash's best work, as well as the greatest albums of the '90s. And while the singer's subsequent three records for the American label produced slowly diminishing returns as his voice deteriorated and the song selection grew more iffy, Cash and Rubin's many sessions produced an abundance of enduring classics. Amazingly, Cash recorded dozens of songs between May (after the death of his wife, the incomparable June Carter Cash) and his death on Sept. 12, and he had just finished contributing liner notes for an exhaustive and lavishly packaged treasure chest of outtakes from the American era. Not counting a pointless greatest-hits disc spanning his last four albums, Cash Unearthed compiles 64 unreleased tracks on four individually titled discs: Who's Gonna Cry (some of which has been heard on the indispensable American Outtakes bootleg), Trouble In Mind (like 1996's Unchained, recorded with Tom Petty & The Heartbreakers, among others), Redemption Songs (a set of covers featuring guests such as Fiona Apple, Nick Cave, and the late Joe Strummer), and My Mother's Hymn Book (an assortment of stripped-down religious songs Cash hailed as his own best work). Though it represented the culmination of a lifelong dream for Cash, My Mother's Hymn Book is the least compelling of the four new albums, largely because its warm-but-straightforward spirituals are accompanied by little of the conflict or contemplation inherent in his best religious material. But the other three, while marred by the occasional misstep, run in varying shades of incredible. Who's Gonna Cry serves as a natural companion piece to 1994's American Recordings, presenting a riveting, near-perfect collection of acoustic meditations on life, death, love, and murder. (The set draws its title from the chilling "The Caretaker," a hair-raising ballad which poses the question, "Who's gonna cry when old John dies?") Trouble In Mind similarly reflects its counterpart: Though it brings to mind Unchained's spirited performances and outstanding peaks, it also has the misfortune of following a disc with more intensity and heft. It does, however, feature the most moving moment on Cash Unearthed. "As Long As The Grass Shall Grow," performed with June Carter Cash, encapsulates both singers' brilliance and love for each other in an appropriately timeless tearjerker. Redemption Songs doles out some classics of its own, with its most notable track pairing Cash with The Clash, as Joe Strummer joins in on a moving cover of Bob Marley's "Redemption Song." Not content to merely fill some gaps in Cash's recent catalog, Cash Unearthed provides an essential tour through the final years of a towering career. Fittingly, that life's work closes on an extended highpoint worthy of the brilliant work that made Cash an eternal icon.