Mountain Roads is oriented, harmonically and melodically, around the note "D," not in the traditional sense of a D major/minor tonality, but with "D" as a note of polarization around which the music revolves. The commissioning quartet sought the composer's permission (which he granted) to produce a version transposed a semitone lower, in which "Db" becomes the note of polarization; a version of the piece in this transposition is also available. - the publisher