The Allen Sapp Score Collection contains manuscript and holograph scores of works composed by Allen Sapp. The collection also contains some of Sapp's drafts, outlines, and twelve-tone row forms and matrices; as well as exercises, analysis, and arrangements of other composer's works completed while at Harvard University.

The collection consists of 79 works by Morton Feldman in either score or part formats (72 scores; 7 sets of parts). All but one item are ink manuscripts on vellum. These served as the masters that Feldman submitted to C. F. Peters and Peters published directly from these masters. Almost all of the manuscripts are in Morton Feldman's hand, except for two scores copied by John Cage and three items in the hand of a music copyist.