The author of this book, Allen Wright, obviously takes his tube audio very seriously indeed, but don't expect this work to tell you how to build a tube compressor or a Boogie soundalike guitar amp. This well‑written book is as entertaining as it is informative, and much of what is discussed is directly relevant to tube mic preamps, and the upgrading of tube equipment in general.
The first section of The Tube Preamp Cookbook is devoted to design philosophies, and includes several interesting anecdotes which illustrate the limits of conventional wisdom when it comes to audio. There's a thorough discussion as to what types of component work best, and even a section on what type of wire to use to build various circuits. Those sceptical about hi‑fi tweaking may view some of the concepts discussed with suspicion, but at least this guy has tried them, and made his decisions based on what he believes to sound best.
The book then continues with a look at basic tube circuit configurations, including a few upgrading suggestions, lavishly illustrated by hand‑drawn circuits. These are followed by a detailed look at the evolution of a couple of very special preamp designs, complete with tales of how they were hurled at the workshop walls on more than one occasion as payment for their intransigence in refusing to respond to treatment for a persistent 'motorboating' problem. If you have any interest in the practical aspects of tube circuitry at all, I think you'll find this book a valuable addition to your collection — it's also a lot of fun to read!