The Lukas Foss Papers span the period 1926 to 2000, with the majority of the materials dating from 1936 to 1995. The collection consists of holograph manuscript scores and parts, sketches, correspondence, business papers, programs, clippings, promotional materials, contracts, and financial documents.

The Music series documents Foss' lengthy and experimental career as a composer, beginning with early opera sketches and piano pieces written before his tenth birthday. Later compositions, especially those which reflect his interests in twelve-tone and aleatory music, are accompanied by extensive supplementary notes, tone rows, mathematical charts, and performance instructions. Photocopied scores and parts often include annotations by Foss or various conductors and performers. Notable holograph scores include Night Music for John Lennon , Elegy for Anne Frank , Renaissance Concerto , The Prairie: Symphonic Suite , Three Airs for Frank O'Hara's Angel , Echoi , M.A.P. (Musicians at Play) , and Tashi . Works are arranged categorically by instrumentation and alphabetically by title therein.

The Correspondence series contains items to and from notable musical figures which are arranged alphabetically by last name. Included are letters from Luciano Berio, Leonard Bernstein, Pierre Boulez, John Cage, Elliott Carter, Aaron Copland, Henry Cowell, Paul Hindemith, Mauricio Kagel, Yehudi Menuhin, Olivier Messiaen, Eugene Ormandy, Krzysztof Penderecki, Mstislav Rostropovich, Karlheinz Stockhausen, Igor Stravinsky, Toru Takemitsu, Iannis Xenackis, and numerous other composers and performers. Correspondence with organizations and lesser known individuals is arranged by subject heading within the Business Papers series. These office files chiefly contain letters, programs, clippings, and legal or financial documents related to Foss' tenure with various orchestras in the United States and abroad, including the Milwaukee Symphony Orchestra, Buffalo Philharmonic Orchestra, Brooklyn Symphony Orchestra, Jerusalem Symphony Orchestra, Tokyo Philharmonic, Vancouver Symphony Orchestra, and the Los Angeles Philharmonic Orchestra.

Folders bearing general titles such as "England" or "Italy" contain assorted materials pertaining to the composer's conducting tours and side projects within these countries. Additional files consist of lecture notes and correspondence with universities, ideas for concert programming, writings by or about Foss, and miscellaneous documents for other topics of interest. The Musical Works Files series contains Foss' extensive file of correspondence, clippings, notes, programs, and promotional items related to specific musical works. These are arranged by title of composition and provide excellent contextual materials for research in musical analysis and performance history. The remaining collection materials can be found in the Miscellany series and consist of programs, articles, and a single writing by Louise Talma.