This letterbook, covering the years 1876-1878, deals primarily with the electric pen, the phonograph, the telephone, and the electric light. About 5 percent of the material is in Edison's hand.

The letterbook is divided into two parts. Pages 1-203 cover the period September 1876-June 1877. Correspondence is primarily in the hand of Charles Batchelor, general manager of the Edison Electrical Pen and Duplicating Press Co. and foreign agent of the Edison Foreign Pen Co. There are also a few letters by Ezra T. Gilliland, superintendent of the foreign company. The correspondence deals chiefly with domestic and foreign sales and service. Non-correspondence includes a few bills and receipts, orders, and shipping lists, which pertain to business operations of the two companies.

Pages 204-500 cover the period April-November 1878. Correspondence is primarily in the hand of Batchelor, William Carman, and Stockton L. Griffin, acting as Edison's secretaries, and relates to the manufacture and international marketing of the telephone and phonograph; the construction and supplying of the Menlo Park laboratory; the formation of the Edison Electric Light Co.; and the initial development, patenting, and promotion of an electric lighting system. Non-correspondence includes bills, receipts, and orders for lumber, hardware, chemicals, and machinery.

The volume also contains two sets of glued-in pages, one preceding the index and the other following page 499. The first contains Edison Foreign Pen Co. correspondence, orders, and shipping lists in Batchelor's hand. The second relates to the telephone and to the Menlo Park laboratory facilities and contains correspondence and orders in the hand of Carman and Griffin. The volume is completely indexed.

The book contains 504 numbered pages. Approximately 50 pages are missing. Seventeen pages which are blank or which duplicate other pages in the letterbook have not been selected.