Series I contains letters exchanged between George Antheil and his colleagues. Many of the correspondents are conductors, music directors, and other individuals involved in the music business. There are also letters from some of George's companions during his time in Europe, such as Ernest Hemingway, James Joyce, and Kurt Weill. The correspondence with Constantin von Sternberg illustrates Sternberg's admiration for Antheil as a young musician while the letters with Mary Louise Curtis Bok Zimbalist illustrate Antheil's financial strain and his need for recognition. Several of the letters are from or to his wife, Böske.