This folder contains correspondence and other documents relating to Edison's efforts to obtain American and foreign patents for his 200-thread record, which he manufactured as the "Amberol" record. The selected documents cover the period 1908-1910. Among the correspondents are Edison, Frank L. Dyer and Dyer Smith of the Legal Department, inventor Ademor N. Petit, and British patent agents Marks & Clerk. Included are affidavits by Edison and Smith regarding the development of the longer-playing record, as well as correspondence concerning claims by the Premier Manufacturing Co., Ltd., of Great Britain to have made similar records.

Approximately 10 percent of the documents have been selected. The items not selected include printed material, detectives' reports, correspondence, and other documents collected for a proposed suit against the Premier Manufacturing Co.