Some performers are beloved by hard-core fans of a genre but hardly visible at all to the wider public. It’s worth chasing down such favorites, for eclecticism is overrated as an artistic philosophy–in the main, it’s deep traditions that yield deep secrets. For bluegrass, the primary current example is the Gibson Brothers, who since the mid-1990s have gradually risen to the top of that scene without ever breaking out beyond the circuit of festivals and small-town fairs that are the music’s natural habitat. Even the Del McCoury Band, who offer a similar mix of profound respect for tradition and significant departure from it, have gained a measure of hipster following, but the farthest the Gibson Brothers have gone is a pair of appearances on A Prairie Home Companion and a few at the Ark, to which they return on September 9 (see Nightspots).

The Gibsons, Eric and Leigh, grew up on a farm in the hardscrabble lands of New York state’s Quebec border, far from the Appalachian bluegrass heartland. Their first instruments came from a store along the road with a big sign, “Guns Guitars Groceries.” Bluegrass has a presence in the folk music culture of upstate New York’s cities but hardly in the small towns like Ellenburg Depot, Mooers, and Churubusco that the brothers knew. The major cultural action in the area came from the giant bingo palaces on the Mohawk reservation just down the road. From this sparse background has grown a remarkable body of work.

The brothers have written most of their own material, supplemented by contributions from the other musicians who have passed through their band over the years and by a few well-chosen covers, including one of The Band’s “Ophelia.” The preponderance of original songs is unusual in bluegrass, whose repertory evolves slowly. The Gibsons’ compositions, beautifully wrought, seem taken from life and family; one good one is “Iron and Diamonds,” about the immigrant iron miners in the area who worked six days a week and played baseball on the seventh.

But the newest Gibson Brothers music is something different. The duet of brothers, the display of arcane family alchemy performed for the world, is one of country music’s oldest traditions. The Gibson Brothers have returned to that tradition with their latest album, Brotherhood, which pays tribute to the classics of the genre from the Monroe Brothers to the Everlys. Like the brother duets of old, the Gibsons dress soberly, in black jackets and ties. They are asserting a permanent place in the bluegrass pantheon, richly deserved.