This folder contains correspondence and other documents relating to the commercial and technical development of the phonograph. Included are letters pertaining to technical problems with the phonograph cylinder and the use of the phonograph in medical and scientific research. Some of the letters deal with the efforts of naturalist Richard L. Garner to obtain a phonograph to record various African languages. Near the end of the folder is a lengthy memorandum by Edison discussing details of various phonograph contracts for the period 1887-1892.

All of the documents have been selected.

Related material can be found in D-92-04 (Edison, T.A. - Articles).