This folder contains correspondence about the technical and commercial development of the phonograph. Some of the letters are by Edison's attorney, Sherburne B. Eaton, and relate to Edison's suit against Ezra T. Gilliland and John C. Tomlinson. There are also letters about Edison's investment in the Phonogram, a monthly phonograph magazine published by Virginia H. McRae; items regarding the lawsuit between the North American Phonograph Co. and the Automatic Phonograph Exhibition Co.; correspondence about musical recording sessions at the West Orange laboratory; and requests for information about phonographs and cylinder recordings. Individual letters pertaining to more than one phonograph company are also filed in this folder.

Approximately 90 percent of the documents have been selected. The following categories of documents have not been selected: letters of transmittal; letters of acknowledgement; routine correspondence concerning phonograph agencies and contracts.