The primary Punch Brother is local mandolin whiz Chris Thile, who until last year fronted Nickel Creek, the closest thing the bluegrass scene has ever had to an emo group. Thile and his bandmates dissolved Nickel Creek in order to more actively pursue other projects, and for Thile that's meant artier projects: On his 2006 solo disc, How to Grow a Woman From the Ground, he complemented cutesy covers of tunes by the Strokes and the White Stripes with thorny, complicated instrumentals defined more by chops than by hooks.

Thile's fellow Punch Brothers—notable bluegrass scenesters all—backed him on How to Grow, and they toured together as the How to Grow a Band. (How emo is that name?) But Punch is their first studio outing as a proper outfit, an occasion for which they've upped the ambition quotient: The album's centerpiece is a four-movement suite called "The Blind Leaving the Blind," which they debuted at Carnegie Hall last March on the invitation of composer John Adams.

Thile has said that he wrote the piece in response to his 2004 divorce, but it's not your standard-issue dashboard confessional. (Well, not totally, anyway: "Tell me what you want me to think," he pouts in the first movement.) Though the material occasionally gathers enough velocity to enter hoedown territory, most of "Blind" is slow and spacey, hewing closer to soundtrack work than to pop; in fact, parts of it could pass as an American counterpart to Jonny Greenwood's score for There Will Be Blood. Absent an accompanying film, the music doesn't always hold your attention the way Thile no doubt thinks it should. Still, it's gorgeous stuff—and proof that this guy sees no end to how far he can extend the roots that still ground him.