This letterbook covers the period November 1905-April 1906. Most of the correspondence is by Edison and John F. Randolph. There are also a few letters by Mina Miller Edison. Included is correspondence with field workers R. D. Casterline, John Morris, and Horace M. Wilson regarding Edison's search for cobalt ore, as well as numerous other letters pertaining to his interest in mines and ores. There are also letters discussing Edison's progress on his improved alkaline storage battery and his plans to reopen his factory in Glen Ridge, New Jersey. In addition, there are items relating to the business of the Edison Portland Cement Co. and to production problems at the cement plant in Stewartsville, New Jersey. Some letters refer to matters of employment and to supplies of chemicals and equipment for the West Orange laboratory. One letter deals with the assignment of Edison's phonograph patents to the New Jersey Patent Co. There are also two letters from Edison to Josiah C. Reiff mentioning Edison's work on quadruplex telegraphy during the 1870s. Among the items pertaining to family and personal matters are letters concerning Edison's diet and sleeping habits, his interest in automobiles, his railroad investments, repairs and improvements at Glenmont, and the upkeep of his winter home in Fort Myers, Florida. Also included is a letter to journalist Arthur Brisbane in which Edison discusses his deafness and relates an anecdote from his days as a telegraph operator in Louisville, Kentucky.
The label on the front cover contains the following notation: "T.A. Edison. Letter Book from Nov. 13 - 1905 to Apr. 1 - 1906." There is an inscription on the spine with similar information. The spine is also stamped "5." The book contains 486 numbered pages and an index. Approximately 30 percent of the book has been selected.