The Philosophy and Practice of Morse Telegraphy (Smith)
Elements of Telegraph Operating (1901)
Twentieth Century Manual of Railway and Commercial Telegraphy (Meyer, 1905)
The Train Dispatcher (Early, 1903)
A Manual of Military Telegraphy (U.S. Army, 1872)
Duplex and Quadruplex Telegraphy (1913)
Manual of Telegraphy Designed for Beginners (Smith, 1865)
A History of Electric Telegraphy to the Year 1837 (Fahie, 1884)
The Anglo-American Telegraphic Code (1894)
Manual of Telegraphy (Williams, 1885)
Telegraphy Railroading, Express and Freight (Soule, 1911)
The Military Telegraph During the Civil War (Plum, 1882)
Tales of the Telegraph (Brady, 1899)
Shaffner's Telegraph Companion (Shaffner, 1854)
Journal of the Telegraph Vol 37-40 (Western Union, 1904-1907)
Official Diagrams of the Postal Telegraph-Cable Company (1906)
Modern Practice of the Electric Telegraph (Pope, 1881)
Telegraph Engineering (Hausmann, 1922)
The Story of the Telegraph in India (Adley, 1866)
Electric Telegraphy (Houston and Kennelly, 1906)
A Handbook of the Electromagnetic Telegraph (Loring, 1878)
Scott's Code, The Ship Owner's Telegraphic Code (Scott, 1882)
Lincoln in the Telegraph Office (Bates, 1907) [A must-read!]
The Multiple Telegraph (A. Graham Bell, 1876)
Examination of the Telegraphic Apparatus (Morse, 1869)
The Telegrapher Vol. VIII (1871-1872)
Western Union Telegraphic Code (Western Union, 1901)
The Electric Telegraph and Its History and Progress (Highton, 1852)
Description of the American Electro Magnetic Telegraph (Vail, 1845) [Wow!]
Journal of the Telegraph Vol 1-2 (Western Union, 1867)