Christy Moore is not only one of the leading voices in Irish folk music, he's also one of the most distinctive. In his American debut at the Birchmere last night, Moore unveiled a rich and resonant instrument that moved with grace and ease between the flowing cello-like melodic lines that coursed through any number of ballads and the exuberant tongue-twisting rhythmic clips used to punctuate the more up-tempo tunes.

Moore covered a number of bases in his opening set: the restless immigrant spirit that took the "traveling people" to both America ("City of Chicago") and Australia ("Good Ship Kangaroo"); the melancholy ache such distances inspired ("Cliffs of Doneen" and "Back Home in Derry"). He also proved to be a radical humanist in his espousal of the shared struggles of the Irish in Franco's Spain ("viva la Quinte Brigada") and of Italians in America (a buzzing version of Woody Guthrie's ode to Sacco and Vanzetti).

But there were wistful love ballads, the best being "Nancy Spain" and a shimmering and eloquent staging of W. B. Yeats' "Song of the Wandering Aenghus" that, thanks to Moore's soft-spun vocals, fairly dripped in hazy tears of times gone by.

Moore also displayed an ingratiating humor, in his banter and in an ode aimed at the reconstitution of St. Patrick's recently demoted sainthood. In one of the most moving moments, Moore set aside his guitar and sang "The Well Below the Valley," accompaying himself only on the bodhran, an Irish drum. The stark melody and ancient rhythms suggested spirits at once pastoral and pagan and confirmed that Moore is one of the most compelling singers on either side of the Atlantic.