Bruce Molsky stands today as the premier old-time fiddler in the world, the defining virtuoso of Appalachia’s timeless folk music traditions. That must feel odd for a former engineer from the Bronx, who didn’t begin a music career until he was forty. But folded into those strange facts is the secret to his unique genius.

In addition to a prolific solo career, performing on fiddle, guitar, banjo and vocals, Molsky frequently joins genre-busting supergroups, like the Grammy-nominated Fiddlers Four, and Mozaik, with Hungarian Nikola Parov, and Celtic giant Donal Lunny. He was on Nickel Creek’s farewell tour, and performs in a trio with Scottish fiddler Aly Bain and Sweden’s great Ale Möller.

Great fiddlers ask him to teach at their fiddle camps, including Alasdair Fraser, Jay Ungar, and Mark O’Connor, who says Molsky has “a mystical awareness of how to bring out the new in something that is old.”

“Young people realize this is a guy who’s tapped into the real deep emotional wellsprings of this music,” says Matt Glaser, director of Berklee’s American Roots Program. “He has a way of removing everything that’s unnecessary; and young people are very hungry for something real. Bruce has that in spades.”

It’s a very personal sense of authenticity that deeply informs his music. Whether performing an ancient reel from Virginia, a Swedish waltz, or a loping cowboy ballad, Molsky presents himself as exactly who he is. Rob Simons, executive director of the Cedar Cultural Center in Minneapolis, says that’s the key to Molsky’s enormous appeal as a live performer: “He’s that unique blend of virtuoso and humble, nice guy that is irresistible to audiences.”

Linda Ronstadt hears that same honest beauty in Molsky’s singing. She placed his singing of “Peg’n'Awl” on her Rhapsody playlist, alongside Edith Piaf, Ella Fitzgerald, and Chet Baker. “Bruce has has that ability to track deep emotion in his voice, without any unnecessary adornment,” she says. “It’s pared back to only the essential architecture of emotion.” And at that profoundly simple and profoundly difficult musical art, Molsky is truly old-time’s master craftsman.

“America’s reigning old time fiddler.” Matt Glaser, fiddler-educator

“The Rembrandt of Appalachian fiddle.” Darol Anger, fiddler

“There’s an incredible power of history and tradition in his vocals.” Linda Ronstadt