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 Frances Schillinger to composer Henry Cowell, noting that she is "delighted that you offered to talk personally to publishers about Joseph's music. If you could take enough time to do this, I would have hopes ...

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."

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.

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 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 (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 Frances Schillinger to composer Henry Cowell, worrying about the upcoming articles in the journal Modern Music that are being published on Joseph Schillinger. "I simply don't understand their antagonistic ...