This book gives a good overall review of tube amplifier design, and has descriptions of the major amplifier topologies such as push-pull, single ended, and output tranformerless. He also covers pre-amp design, and components. The author does tend to dismiss all types other than push-pull pentode as being frivolous. Consequently, most of the output amplifier circuit designs where he goes into detail, are P-P pentode. Nevertheless, no matter what kind of tube amplifier you are designing or modifying, you will find some useful information in this book.