This folder is mainly correspondence relating to his business, as well as his initial research in what became his book, Pioneers of Brass. There are numerous letters from A. W. Lehman, a brass player in the U.S. Marine Band (The President's Own), both regarding particular pieces of recorded music, as well information about Lehman's touring schedules and music in general. There are postcards from him to Bridges, as well as programs for concerts by the Marine Band during the decade. There are several letters from Frank McGrann as well as one from Arthur Pryor, Jr., concerning his father, Arthur Pryor, and a letter from Joel Duroe. There are several letters from Vincent Bach.