Lyricist and librettist (1873–1963) of fifty musical comedies who served as Oscar Hammerstein II's mentor. DS, two pages, 8.5 x 11, March 9, 1936. Harbach, who had already conveyed motion picture rights to MGM for his operetta ‘Firefly,’ further grants permission to interpolate music which is not written by Rudolf Friml, the original composer, so long as Friml agrees with such use. A light shade of toning, and staple and punch holes to the top, otherwise fine condition. RRAuction COA.