The primary way of discovering Yale's rich archival collections is via Archives at Yale: https://archives.yale.edu/. Archival collections are organized by name (i.e., who is the person that the archive is documenting, say Jonathan Edwards or Charles Ives) or by corporate/institutional entity (e.g.,  Society for the Publication of American Music, Papers). So, a good way to search this database is by person/name.

Here are a few collections that hold items of interest for this class:

Benny Goodman Papers

The Benny Goodman Papers are located at the Music Library The papers include scores and/or parts to musical arrangements written for Benny Goodman's bands, orchestras, and combos. The Papers also include published music in Goodman's collection; correspondence (including letters from many prominent musicians and political figures); photographs; scrapbooks; concert programs, films, and more. See the online exhibit: Preaching to the Choir: American Jazz and Cold War Diplomacy in Southeast Asia

Konstanty Jeleński Papers

The Konstanty Jeleński papers are located at the Beinecke Library The papers include correspondence, writings and other material that documents Konstanty Jeleński's editorial work, literary criticism and involvement with several cultural organizations, including the Congress for Cultural Freedom.

Marshall Bartholomew Papers

The Marshall Bartholomew Papers are located at the Music Library. Marshall Bartholomew (1885-1978) was director of the Yale Glee Club and of undergraduate musical activities at Yale from 1921 to 1953. He founded the International Student Musical Council in 1931 to promote international good will through singing, and he served in various relief capacities during both World Wars. All of his life he was especially active as a composer and arranger of songs for singing groups. His final major project was research into the history of music at Yale in preparation for a book on the subject, which was not completed. All of these activities are represented in his Papers. There is an unprocessed part of the papers, which includes Bartholomew's extensive diaries.  Typescript digests of the diaries and correspondence may be found in the processed portion.

Virgil Thomson Papers

The Virgil Thomson Papers, at the Music Library, contain the manuscript scores and sketches of Thomson's musical compositions, printed copies of books and music by Thomson, and a voluminous correspondence to and from many important American and French cultural figures since 1920. IMPORTANTLY, the correspondence includes a section relating to Thomson's dealings with the United States Government and with the Congress for Cultural Freedom (and N. Nabokov). 

Robert Shaw Papers

The Robert Shaw Papers are located at the Music Library. Robert Shaw and his chorale did a concert tour of the Soviet Union in 1962. They happened to be there at the time of the Cuban Missile Crisis! The Shaw Papers contain a great deal of material pertaining to this trip. Shaw’s decision to perform the B Minor Mass was controversial but successful, and he also made contact with some dissidents, including the artist Yuri Titov. Contact me to find out how you can consult documents relating to that trip...

Vladimir Horowitz Papers

In 1986, Horowitz made an important concert trip to the Soviet Union after an absence of 61 years. He was later awarded the United States Presidential Medal of Freedom by President Reagan. The Horowitz Papers, located at the Music Library document these important events. Contact me to find out how you can consult documents relating to that trip...