Robert Plant, Alison Krauss Raise Bar with Raising Sand

For those who only know Robert Plant as the primal screamer behind such Led Zeppelin classics as "The Immigrant Song" and "Whole Lotta Love," his pairing with bluegrass star Alison Krauss may come as a surprise.

Zeppelin wasn't all about bombast though. For every "Black Dog," there was "That's the Way." For every "Rock and Roll," there was "Gallows Pole." Indeed, Plant's roots are as much in country, blues and folk as they are in rock and roll and heavy metal. Always one to experiment musically and a professed fan of Krauss, Plant phoned her several years ago to express interest in working with her. It wasn't until their duet at a Leadbelly tribute at the Rock and Roll Hall of Fame though that they considered recording an album.

That album is Raising Sand. Produced by T Bone Burnett, with songs selected by Burnett with input from Plant and Krauss, Raising Sand is a diverse mix of blues, country, folk and roots rock songs from a wide range of writers, including: Tom Waits, Gene Clark, Phil and Don Everly, Little Milton Campbell, Mel Tillis and Sam Phillips.

The combination works to great effect, with Plant and Krauss sharing lead vocals on a number of songs, including a fun romp through the Everly Brothers' "Gone Gone Gone (Done Moved On)," a bluesy take on "Rich Woman" that would be at home on Plant's Mighty Rearranger disc and a version of Mel Tillis' "Stick With Me Baby" brimming with the hope and optimism of a couple in love against all odds.

The solo tracks work too, highlighted by Krauss' haunting takes on Phillips' "Sister Rosetta Goes Before Us" and Waits' and Kathleen Brennan's "Trampled Rose." Plant's emotional reading of Clark's "Polly Come Home" and a heavy take on Townes Van Zandt's "Nothin'" are highlights as well, with Plant's and Krauss' musical worlds colliding on the latter with its country fiddles over Zeppelinesque guitars.

Plant even covers himself, with a stripped down version of "Please Read the Letter" from 1998's underappreciated album with Jimmy Page, Walking into Clarksdale. A song of breakup, Krauss' harmonies offer the woman's perspective - as if they were both reading the same letter.

Backed by a crack band including Marc Ribot, Norman Blake, Mike Seeger, Jay Bellerose, and Dennis Crouch, Raising Sand sounds at once familiar and new. Two forces in their own right, Plant and Krauss combine to make something fresh and exciting. With rumors of a tour, the possibilities of Plant and Krauss reinterpreting each other's catalogs makes this pairing even more intriguing. If Raising Sand is any indication, theirs could be the must-see tour of 2008.