This folder contains correspondence and other documents relating to the technical and commercial development of phonographs. Included are letters from collectors, independent experimenters, and other individuals writing to Edison with advice or requests. A sample of these unsolicited letters has been selected.

Approximately 20 percent of the documents have been selected. The following categories of documents have not been selected: unsolicited letters pertaining to the catalog of Edison recordings, including letters from prospective singers and songwriters; requests for Edison to donate phonographs to organizations and individuals; requests for Edison's advice and assistance on technical matters or his assistance in improving or promoting inventions; unsolicited requests for recordings of Edison's voice; and foreign-language circulars. All of the unselected letters were either unanswered or received perfunctory replies from Edison or his staff.