Receipt from the New York Times Company, recording that composer Henry Cowell was paid for his article "Case for system" that appeared in the Sunday Section of the newspaper.

Postcard from ethnomusiologist Sidney Robertson Cowell to Frances Schillinger, asking about the Rhythmicon [the first electronic rhythm machine built by Russian inventor Louis Theremin]: "could a composer afford to buy it? ...

Letter from ethnomusicologist Sidney Robertson Cowell to Frances Schillinger, letting her know that "Henry has been ill…and it is unfortunately impossible for him to undertake to write anything - he is sorry."

Letter from composer Henry Cowell to Arnold Shaw, letting Shaw know that "I'll get at the writing of the introductory remar[k]s pronto."

Letter (in German) from Arthur Friedheim to his wife, Madeleine; written while Friedheim was teaching in Toronto.

Letter (in German) from Arthur Friedheim to his wife, Madeleine; written while Friedheim was teaching in Toronto.

Letter (in German) from Arthur Friedheim to his wife, Madeleine; written while Friedheim was teaching in Toronto.

Letter from composer Henry Cowell to Frances Schillinger thanking her for "reprinted notices - send me any and all there are!"

Letter from composer Henry Cowell to Frances Schillinger: "I am glad to hear of your book on Joseph."

Letter from Russian scientist Léon Thérémin to Frances Schillinger (typed manuscript of original handwritten note) discussing both Joseph Schillinger and composer Henry Cowell.