The collection contains the manuscripts of Sessions' compositions reflecting his use of the 12-tone system of composition and ranging from exercises and studies to concertos, sonatas, operas ("Lancelot and Elaine" and "Montezuma"), and symphonies (1 through 9). Also included are miscellaneous musical works such as divertimenti, nocturnes, chorale studies, quintets, and the cantata "When Lilacs Last in the Dooryard Bloom'd." In addition, there are manuscripts for two prose works, "The Musical Experience," a lecture delivered at the Julliard School of Music in 1947, and an article, "To the Editor," which appeared in Perspectives of New Music in 1967.

Additions to the papers include ozalid copies of various cantatas, concertos, symphonies, and miscellaneous works, original scores for a violin concerto, sketches for Symphony No. 1, correspondence with Luigi Dallapiccola and two musical manuscripts by Jean Binet. New additions include a small "Composer's notebook" which he carried in his pocket; two letters to Carl Miller, an ALS to Arthur Mende; a letter dated Jan. 14, 2001, from Anne Welch Gordon to "Princeton University Music Dept." regarding giving the "Composer's notebook and the correspondence to the Music Library; an unidentified manuscript, and photocopies of correspondence.

For information on the Roger Sessions Society, visit: http://www.uncwil.edu/music/sessionssociety/