This letterbook covers the period January 1898-December 1899. Most of the correspondence is by Edison or Walter S. Mallory, vice-president of the company. The letters deal mainly with personnel matters, company financial obligations, briquette production, and alterations at the Ogden works. Some of the letters relate to Mallory's personal affairs. A few documents pertain to cement and the formation of the Edison Portland Cement Co. There is also material regarding phonograph orders, the assets of the Edison Phonograph Works, and the purchase of land adjoining Edison's West Orange laboratory. Two letters concern Edison's children, Thomas and Madeleine. The front cover is labeled "N.J. & Pa. Conc. Wks Personal Letter Book of W. S. Mallory from Jan. 27 [1898] to Nov 30, 1899." The book contains 494 numbered pages and an index. Less than 20 percent of the book has been selected. Some of the letters may be difficult to read due to very faint green ink and purple smeared ink. Related letterbooks can be found in the Walter S. Mallory Papers (Special Collections Series).