On the surface, the imagination boggles when confronted with a musical collaboration between two such seemingly polar opposite talents as Americana/bluegrass goddess Alison Krauss and shouting, yowling Led Zeppelin frontman Robert Plant. But under producer/bassist T-Bone Burnett's direction, there's no superstardom at play here, just a cadre of singularly talented people painting something novel, interesting and completely alien to the normal calculated commercial processes. Plant sings with an unsuspected subtlety and mesmerizing prettiness, while Burnett's eclectic selection of material allows Krauss to step completely out of character and let her voice soar from Edith Piaf to the Everly Brothers. Her amazing vocal on "Trampled Rose" is at once beautiful and hauntingly dramatic, and Plant's greatness rings through in a brilliant remake of the Brit-rock classic "Fortune Teller." On rockabilly burners like the Everlys' "Gone, Gone, Gone" or beautifully crafted folk obscurities like "Killing the Blues," Krauss and Plant virtually redefine duet, or at least render a definitive modern example. Laid over Burnett's drum-centric arrangements and adventurous rhythms, their hypnotic harmonies reverberate long after this brilliant record is over.