It seems like a truly bizarre partnership: legendary Rock God, famous for a hedonistic career spanning four decades, and celebrated country artist who's been lauded for her work with bluegrass band Union Station and on the O Brother, Where Art Thou? soundtrack. On paper, it looks like it'd never work. Surprisingly, however, Robert Plant and Alison Krauss have together crafted one of the most beautifully understated albums of 2007. A collection of cover songs ranging from Tom Waits to the Everly Brothers and beyond, Raising Sand breathes new life into songs that either time or neglect have coated in a mantle of dust. There's a gorgeous, analogue-style warmth to T. Bone Burnett's impeccable production, too - which ensures that the smouldering, dream-like country folk of Rich Woman, the muted tension of Gene Clark song Polly Come Home, or the '60s pop-meets-blues-groove of Fortune Teller improve upon repeated listening. Particular highlights include the almost rockabilly-style country of Gone Gone Gone (Done Moved On), the poignant, ghostly beauty of Trampled Rose, and the trembling, uptempo rock of Nothin'. Plant's voice has indubitably improved with age, and is strikingly suited to this style of music, while the wonderful Krauss's haunting lilt has never sounded better. Together, their voices meld like a golden syrup, creating a union that seems initially odd, but presumably fateful. Led who?