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. Also included are letters about musical recording sessions at the West Orange laboratory, correspondence regarding phonograph exhibitions, 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 60 percent of the documents have been selected. The following categories of documents have not been selected: routine business correspondence involving more than one Edison phonograph company; letters of transmittal and acknowledgement; duplicate copies of selected documents.