The collection contains photocopies of musical scores for 127 tangos for solo piano from 127 composers. The collection also documents the process by which Mikhashoff commissioned and performed the tangos. It includes correspondence, Mikhashoff's research into the history of the tango, and performance materials (i.e. programs and reviews). Composers commissioned for this project include Milton Babbitt, Lukas Foss, Otto Luening, Conlon Nancarrow, Luis de Pablo,and Nils Vigeland.

The collection contains approximately 1300 scores, half of which bear markings entered by Mikhashoff or his colleagues in preparation for performance. The collection includes manuscripts and print publications, both originals and reproductions.

The collection contains 55 manuscript scores, many of them reproductions by photocopy or ozalid, 1 published score, 3 compact discs containing mp3 audio files of 10 works, 2 audio compact discs, and 1 DVD.

The Livingston Gearhart Collection of Scores contains compositions and arrangements by Gearhart in published and manuscript forms, as well as sketches and incomplete works. It also contains published scores by other composers annotated by Gearhart.

The collection consists of 123 scores of compositions by Leo Smit, principally in copies of holographs. There are 21 scores of works by other composers arranged or transcribed by Smit. The remaining 41 scores are works by other composers either inscribed to Smit or marked for performance by Smit.

The collection contains scores of 33 musical works by composer, singer, and librarian Joseph Chouinard.

The collection contains scores of five compositions by John Myhill in varied states of completion and a folder of sketches and musical analyses. The collection also contains a folder of prose writings and a single piece of correspondence to Myhill.

The collection contains scores and parts of twenty original compositions by Friedrich Otto Trautmann, a composer and organist who lived in Germany and England in the late nineteenth to early twentieth century.

The collection contains scores and parts of original compositions and arrangements by Frederick Slee. It also includes transcriptions of works by composers such as J.S. Bach, Mozart, and Haydn, as well as a lesson for recorder.

This is the largest collection of Ferdinand Praeger's manuscripts in the world, consisting of approximately 480 works. The majority of the works are for piano, but the collection also includes chamber music for strings, large ensemble works, vocal works, and sketches. The dated works range from 1829-1891, but many works are undated.