For her second album, "Follow Me Down," released on the Sugar Hill label just shy of her 20th birthday, Jarosz enlisted some impressive musicians: Béla Fleck, Edgar Meyer, Dan Tyminski, Shawn Colvin, Darrell Scott, Mark Schatz, Jerry Douglas, Chris Thile, Noam Pikelny, and the list of guest artists just keeps going. By any measure, she's gathered an all-star lineup and then some, and in so doing she has placed herself in a league of heavy hitters. Given her playing, writing and interpretive skills, that's exactly where she deserves to be. This is a young musician who seems to know who she is and where she wants to go, and who has the level of musicianship that she needs to get there.

Like the Punch Brothers or bands like Crooked Still, Jarosz is arguably on the crest of a wave of young musicians who, with spectacular chops and equal confidence, are putting the grit and energy back into acoustic and bluegrass-based music. Her sound is challenging, layered, complex and beautiful, and based in a broad, rich swath of American music.

In Jarosz's world the Louvin Brothers and Bill Monroe sit comfortably next to Radiohead and Tom Waits (she has covered songs by both). It's a world where old-time songs, as in the case on the haunting "Annabelle Lee," can have a drum kit (at least on the album version); a world where she can play clawhammer banjo one moment and a masterful mandolin solo the next.

Her writing is fresh and bold, and sparkles most when delivered in the first person, as on songs like "Come Around" and "My Muse." It's a testament to her writing that it's hard to tell the new from the old, the originals from the covers.

In the end Jarosz reminds us that, in many ways, youth, energy and experimentation is perhaps the only truly abiding hallmark of American music. Bill Monroe didn't sit back and play the music from the past, rather he took those traditions and made something new. And that's exactly what Sarah Jarosz is doing, too.