Etta Baker is a virtuoso performer in a style heard infrequently these days–the finger-picked guitar tradition known as the Piedmont blues. Using a two- and three-fingered technique similar to that of other North Carolina guitarists such as Elizabeth Cotten, Rev. Gary Davis, and Blind Boy Fuller, Etta creates music that is remarkable in its range and depth. It’s a Gregorian chant at least 11 centuries old, was rearranged by French…