This is a terrific book for everybody interested in mastering or working with audio at any other stage in the production process. It covers all sorts of concepts, expaining why they are important to understand and how to apply your knowledge. Once I have finished reading it first time, I will find it a great reference source when I need to be reminded about decibells, dithering, frequency ranges and a whole encyclopedia of other topics. I won't even try to list all them all here, but suffice to say that if it is relevant to the quality of recorded audio, it is explained excellently in this book. Bob Katz clearly knows his subject inside out and is a patient, enthusiastic teacher.
The book makes it clear that there are no quick answers to the question 'how do I master?' and there is a lot of densely packed technical information that some may find daunting. However, it is so well written that anybody with a genuine interest will find it enormously rewarding and will certainly learn a lot more than they would from any guide that tried to provide quick answers. Some people talk about mastering as if it is a black art that mere mortals could never fully understand, whereas Bob Katz makes it clear that you can learn to do it well so long as you are prepared to learn a lot of theory and train your own ears.
As much care has gone into the details of presentation as the editorial content. The pages are made of nice, thick paper, there are plenty of illustrations and even a lovely fold-out poster in the front illustrating the note-ranges of all the instruments in the orchestra.
Having almost finished reading the book once, I have been amazed at how much I didn't know I needed to know, but I have also finally got a handle on many concepts I knew I didn't know well enough. The things I have learned in this book will immediately affect the way I work with audio right from recording, to editing, mixing and, of course, mastering.