Saga of the Vacuum Tube by Gerald F. J. Tyne. Blue cover vintage 1977 first edition first printing. 494 numbered pages. Clean and sound internally. There is some external edge/ shelf wear but still a nice clean copy. I have lots of electronic, radio, sound, recording, etc books pamphlets brochures and manuals to list. They all came from an estate of a local gentleman who was chief engineer at a radio station, had his own radio show and eventually had his own Christian radio station. Thanks for looking!