Arthur Waldeck (1899-1965) was a New York-based voice teacher. The collection consists of Waldeck's letters to and from renowned music theorist Heinrich Schenker (1868-1935), as well as Waldeck's translations into English and heavily annotated copies of Schenker's works, written and published in German.

Austrian-born American music theorist Felix Salzer (1901-1986) furthered the system of musical analysis developed by Heinrich Schenker and was a faculty member and executive director of the Mannes College of Music. The collection contains biographical information, Salzer's honorary doctorate from Mannes and materials and photographs relating to the degree conferral ceremony, as well as vacation photographs of Salzer and his wife, Hedwig Lindtberg.