This double-disc collection from Ireland's most beloved traditional ensemble spans their lengthy history with tracks from 1977 to 2002, and neatly traverses their inclinations from Celtic conservationism to globe-trotting experimentation. The Essential Chieftains also does a good job in representing some of the star power that Paddy Moloney's men have managed to draw around their efforts. Five cuts from Down the Old Plank Road, their second trip to Nashville, spotlight Alison Krauss, Béla Fleck, Emmylou Harris, Edgar Meyer, the Nitty Gritty Dirt Band, and Buddy & Julie Miller, for starters. Tears of Stone, their all-star Irish effort, featured the Corrs and the Rankins, both cited here. Elsewhere in the '90s were collaborations with Linda Ronstadt, Elvis Costello, Marianne Faithfull, Los Lobos, Ricky Skaggs, Ry Cooder, Sinéad O'Connor, Jackson Brown, and myriad film and concert orchestras. But things were not always thus, as the first disc in this collection reminds us. Treading lightly over material covered in depth on The Claddagh Years and other comps, The Essential culls late-'70s gems that show the streamlined proficiency of the group, whose definitive lineup includes Moloney, Sean Potts, Martin Fay, Kevin Conneff, Mick Turbidy, and the late harpist Derek Bell. Certainly no need for all the boldface names back then. Yet if this set spends more time tracking the ensemble's peregrinations from Ireland to France to China to Nashville (twice) and back, that -- along with the guest stars -- is an essential part of the Chieftains' story.