Here's how collaborations between name artists tend to go: You do your thing, I'll do mine, we'll try and play to each other's strengths and count on something unique happening. That's not necessarily a formula for failure. There was nothing wrong, for example, with the recent Mark Knopfler/Emmylou Harris album All The Roadrunning, which radiated real chemistry. But in adding A and B and coming up with AB, the album couldn't avoid a certain predictability. It had twice the star power but half the revelations of Knopfler's and Harris' personal bests. Raising Sand isn't that kind of album or that kind of collaboration. Like All The Roadrunning, it marks the unlikely (for some) first-time pairing of a legendary British rocker and a sweetheart of American country music: Robert Plant, a forefather of heavy metal, and Alison Krauss, poised young leader of the modern bluegrass movement. But its marquee meeting is only a starting point for what unfolds. Guided by a third partner of equal status and importance, producer T Bone Burnett, Plant and Krauss take leave of their respective elements and find new common ground in Burnett's darkly luminous chamber sound and roots connoisseur's playlist of neglected favorites. And the songs -- by Doc Watson and the Everly Brothers, Gene Clark and Townes Van Zandt, Little Milton and Allen Toussaint, Tom Waits and Plant himself -- assert their own authority, individually and collectively. Talk about the sum of your parts: With a stellar cast of T Bone regulars including cutting-edge guitarist Marc Ribot, bassist Dennis Crouch and drummer Jay Bellerose, Raising Sand is like a Rubik's Cube of artistic co-involvement. Approach it from any one angle and you're not going to solve the puzzle of its success. Like many of his English peers, Plant established his roots cred long ago through his involvement in blues and R&B. (A world music maven now, he is a featured contributor on the new Fats Domino tribute album Goin' Home.) Krauss has always been conversant with pop; in interviews, she has even professed her love for metal. Far from seeking to impose their individual styles on the wide-ranging, eras-spanning material here, though, they take an unexpectedly subdued, reflective, sometimes self-effacing approach. Equal partners on some songs, unequal on others, featured soloists on still others, they throw out the rulebook on duet albums. Their harmonies couldn't be more fetching on "Killing The Blues", a wistful gem by Chris Isaak bassist Rowland Salley, on which Greg Leisz's pedal steel arches over them like a rainbow over gold. But at other times they recede into the music, letting the dialogue between guitars and other strings -- doubled, overdubbed, electric over acoustic -- take precedence. Hearing these two powerful singers reduce themselves to a whisper can be a bit disconcerting. But if there are times the songs cry out for more vocal presence, the overall effect is oddly seductive. Even if you've previously heard these songs, Raising Sand gets you to hear them as if for the first time. Above and beyond the attraction of the Plant-Krauss summit, this recording is a passionate testament to the transporting power of American music, hallowed be its name. The emotional landscape of Raising Sand stretches far and wide. At one end is the eternal longing of Sam Phillips' "Sister Rosetta Goes Before Us", a new, Kurt Weill-ish tune by Burnett's former wife (with whom he remains close) on which Krauss' lovely, piercing clarity speaks to the "echoes of light that shine like stars after they're gone." At the other end is the stark, downbeat denial of Van Zandt's "Nothin'". The least representative cut on the album, it receives a swarming, fuzz-toned '70s treatment, with Krauss making like onetime Dylan cohort Scarlet Rivera on violin. Not until the airy rockabilly rumble of the fifth song, the Everlys' "Gone Gone Gone (Done Moved On)" from the mid-'60s, does Raising Sand allow itself any real rockish energy. Even then, the sighing, wordless vocal harmonies bridging the verses keep it in ethereal mode. That isn't to say the song or the album is short on licks. Ribot's popping lines help turn Little Milton's "Let Your Loss Be Your Lesson", a B-side delight from his Stax years, into a plucky Loretta Lynn-type tune for Krauss. (With Burnett adding his six-string bass to Crouch's standup, you can almost hear the missing horns.) Burnett and Ribot's quavering electric effects introduce a streak of modern voodoo to "Rich Woman", a mid-'50s hit for New Orleans singer Li'l Millet & His Creole Kings. This is one of Burnett's most string-centric productions. Except for the toy piano and pump organ featured on a theatrical reading of Tom Waits' "Trampled Rose" -- with Ribot swapping the banjo he played on the 2004 original for dobro -- there are no keyboards. Fresh off the striking, innovative sound of his own underrated recent album, The True False Identity, Burnett allows himself a stronger profile here as a musician than he has on all but a few of his productions. Krauss contributed to Burnett's soundtracks for O Brother, Where Art Thou? and Cold Mountain. Still, she and Plant, who sang together for the first time at a Lead Belly tribute a few years back, both might have been expected to project a certain self-consciousness on an album as different and ambitious as Raising Sand. But with Burnett providing inspiration and support, they seem right at home with the concept. However much Plant cleans up his act -- and he can sound as pure as a choirboy here -- he hasn't forgotten who he is, as he reminds us with occasional injections of his mentholated blues moans ("Well, well, well, well, well, welllllllll"). But as reflected by his moving, beautifully restrained performance on "Please Read The Letter", a haunting, sepia-toned lament he wrote with Jimmy Page during their post-Zep partnership, he continues to grow as a singer. Even on the onetime Who staple "Fortune Teller", written by Toussaint in the early '60s under the pseudonym Naomi Neville, the Zepinator re-plants himself in this new collaborative turf without looking back.