This folder contains copies of outgoing correspondence similar to the material found in the Letterbook Series. Much of the correspondence was typed by Edison's office staff. Most of the letters cover the period November-December 1887 and pertain to the phonograph, the phonoplex system, mining and ore milling, electric lighting, and other technical and business interests. Some of the letters deal with the construction of the West Orange laboratory and the installation of electric wires at Glenmont. There is also some personal correspondence. Much of the correspondence is by Edison's private secretary, Alfred O. Tate. There are also letters by Edison's associate Charles Batchelor on behalf of the West Orange laboratory.

Approximately 40 percent of the documents have been selected. The following categories of documents have not been selected: personal correspondence by Tate and Batchelor; routine correspondence regarding orders, shipments, employee accounts, financial transactions, and sales and transfers of stock; routine responses to individuals seeking employment, requesting or offering advice, or making other unsolicited inquiries; letters of transmittal and acknowledgment; duplicate copies of selected documents.