London: Benn Brothers Limited 1921-1924. First Edition. Vol. 1: 282 pages. Vol 2: 227 pages. Vol 3: 339 pages. 3 volumes complete. 4to. Nicely rebound in faux leather cloth binding with gilt spine lettering and inset on front panels with original cloth title, author, and volume numbers laid down (Volume III label partly faded). Occasional library stamp or notation internally, otherwise a clean tight set. Properly discarded. Includes pocket of diagrams inside rear cover. Near Fine. Cloth. 
Volume 1: Circuits and Apparatus as Used in the Public Services. Includes chapters on the Strowger, Siemens, Western Electric, and other systems. Volume 2: Auxiliary Services and Private Branch Exchanges, Includes a brief supplement to Vol 1. Volume 3: Large Multi-office Automatic Systems; Semi-Automatic Working; Miscellaneous Systems; Layout and Wiring' Power Plant; Traffic.
A "Very detailed survey of British and other practice, including many large folding diagrams." (Sterling and Shiers History of Telecommunications Technology, 7-044 starred entry)
Highly technical, useful reference for the historian, collector, or restoration specialist. Many photographs and diagrams.