This 1934 tube manual, here reproduced almost exactly as it was first pub- lished, marks a fresh departure in vacuum tube information presentation. Although published during one of America's most severe economic depres- sions, it covers the then available RCA tube line, with its primary emphasis on radio applications. Television was still in the early experimental stages of discovery and development and audio, as a separate discipline, was still in its infancy.

The presentation of individual tube information is far more extensive for each one than in later editions which are shortened to accommodate the rapid expansion of tube offerings. The manual opens with RCA's summary of tube fundamentals, covering the first 29 pages, with clear illustrations of tube actions. A spread of photos of tube manufacture follows, with the next hundred pages given to individual tube performance data. The final sixteen pages cover tube testing, suggested circuits including nine receivers, four audio amps and a microphone preamp. Operating conditions for resistance coupled A-F amplifiers is summarized in a table and tube bulb profiles are supplied on p. 151. A two-page index completes the book.

This manual RC-12 is an early historical snapshot of the growing tube tech- nology in the United States, but also a useful guide to the very early tubes which it details. It will be especially useful to those who are restorers of antique equipment, but also a useful look at one period of thermionic valve development for any tube enthusiast.