This letterbook covers the period January 1898-August 1899. Most of the correspondence is by Edison and John F. Randolph. Many of the documents relate to mining and ore milling. Included are letters concerning Edison's operations at Ogden, N.J. and the factors that led to the temporary shut down of the plant during the winter of 1898-1899; his investment in a dry placer mill near Santa Fe, New Mexico; and the organization of the Edison Ore Milling Syndicate, Ltd. Some of the letters pertain to Edison's work on a compressed air reheater and the formation of the Edison-Saunders Compressed Air Co. Other letters deal with his plans to manufacture Portland cement and the organization of the Edison Portland Cement Co. In addition, there is correspondence about electric meters, a process for using coal dust as fuel for steam boilers, the phonograph, motion pictures, the fluoroscope, and x-rays.

Included also are numerous letters about Edison's personal finances and the financial affairs of his children, Marion, Thomas, and William; proposed business deals with Edison's former associates, Josiah Reiff and Edward H. Johnson; the management of his property at Fort Myers, Florida; and his debts to Sigmund Bergmann and to the estate of Robert L. Cutting, Jr. Appearing on page 145 is a letter to Samuel Insull about the origin of the phrase "central stations."

The front cover is marked "1898 1899" and is labeled "Letters of Thomas A. Edison. From. January 31st, 1898. To. August 29th, 1899." The spine is stamped "Letters" and is labeled "T.A.E. Letters from Jan-31 1898 to Aug 29 1899 2 ." The book contains 700 numbered pages and an index. Approximately 20 percent of the book has been selected.