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.

The International Schenker Symposium, a conference dedicated to furthering the study of the system of music theory developed by Heinrich Schenker, was held at the Mannes School of Music septennially from 1985 to 2013. The collection contains papers presented and administrative files primarily from the first symposium in 1985, and the fourth symposium in 2006. Audio recordings of portions of the 1985, 2006, and 2013 symposia are also included.