This book is a collection of wise precepts by one of the greatest vocal teachers in history. G.B. Lamperti was a world-recognized expert in the field, who taught hundreds of the most successful singers of his day. Lamperti was not an academic theoretician--he was a practicing expert with world-class credentials.
I admit that at first, I did not realize the significance of this book. At first glance, you might be tempted (as I was, briefly) to write off this book as an assortment of light fluff. If you make that mistake, you will be missing out on some of the most important, as well as inspirational, ideas central to the art of singing.
Note that this is not a book on vocal technique, or a list of vocal exercises, that upon mastering, you will have arrived as a great singer. It is important to understand Lamperti's perspective on the art of singing. He sees vocal "gymnastics" as a way of sensitizing your body and mind to the art, with the ultimate goal of diction, breath-control, and vibration working together as one. Here's Lamperti:
"Mental and physical gymnastics must of necessity be specific in order to stimulate and sensitize the various parts of brain and body. But these methodical exercises should not be confused with final singing because they inhibit nature's instinctive processes."
"Fundamental exercises are only to make the body and imagination more supple and sensitive, to respond to the desire to produce a beautiful tone and sustain a melody."
The vocal precepts are loosely categorized into short chapters. I found it helpful to go through the entire book quickly, to get a feel for the arrangement. It's hard to pick just a few key precepts, but here are a couple--just to give a slight taste:
"Singing will be awkward unless focused vibration, distinct pronunciation, and compressed breathing remain inseparably linked together."
"Sensitive co-action of the whole muscular and nervous energy is the condition demanded for the production of pure tone."
As I re-read this book, I realize that I only understand Lamperti a bit. I have much more to learn. This short review does not do the book justice. Read his book many times. If you don't see the importance of his ideas, read it again, because you're missing the key to singing.