Serge Prokofiev (1891–1953) was a Russian and Soviet composer, pianist and conductor, and seminal figure in the history of twentieth-century music. The Serge Prokofiev Archive (SPA) contains 58 original music manuscripts and over 10,000 letters and documents primarily from 1918-1936, the years Prokofiev spent in the West. The SPA also includes an expansive collection of music manuscript copies, published scores, concert programs, scholarly books and articles, photographs, and audio and video material, making it the premier research collection for studying Prokofiev's life, work and legacy.

This collection documents the musical career of Yella Pessl, a harpsichordist, pianist and organist.

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.