This letterbook covers the period August 1887-November 1888. Many of the letters are by Edison. There is also correspondence by Charles Batchelor, Alfred O. Tate, and John F. Randolph. Included are letters relating to ore separator patents in the United Kingdom, phonoplex sales in the United States and the United Kingdom, proposed central stations in Japan and Korea, and the international search for sources of bamboo for electric light filaments. Other letters pertain to Glenmont and to the construction of the West Orange laboratory. Some material concerns the finances and operations of the West Orange laboratory and the various Edison companies. The front cover is marked "1887-1888 Indexed." The book contains 482 numbered pages and an index. Pages 365-482 are blank. Approximately 30 percent of the book has been selected. Courtesy of Thomas Edison National Historical Park.