The back cover of this book states, ˝A Complete training guide to restoring vacuum-tube and transistor radios.˝ And an excerpt of the description notes, ˝In addition to covering the vacuum tube circuits of radios made before 1950, author Joseph J. Carr gives you transistor theory and practice...˝ Unfortunately, not a single mention is made of transistors or transistor theory in the book. Other than that omission, the book is a good guide to the theory of tube radio circuits and contains some chapters on tube circuit troubleshooting, safety, and test equipment. Some electronic knowledge is helpful in understanding this fairly concise book.