I bought this book because I was concerned that I felt like I was gasping for air all the time. I simply looked for something about "breathing" on amazon and found this book.
The book itself is repetitive and leaves you wondering exactly what it is your meant to do. The contents of the book could easily be written on a few pages so they draw it out a little.
After a few reads I worked out what it actually involved, which isn't actually a great deal (I didnt make any dietry changes as it was little different from my diet now). I just did the breathing alterations / exercises. Using their method of measuring how much you are currently "over-breathing" my results were very poor. The first few days were hard, sleeping with tape over my mouth (when I was very congested) led me to wake up in a panic thinking I wasn't getting enough air. I got used to it soon enough.
The thing I noticed most quickly (within a day or 2) is that I had A LOT more energy. Before, I felt tired all of the time, and would really have to fight not to fall asleep at work sometimes, even after a full nights sleep.
Other changes I have noticed : a healthy glow in my face, generally happier, I feel fitter, I dont feel short of breath. My congestion finally cleared after about a month and I very rarely feel short of breath now. Also, I can excercise without breathing through my mouth at all which is quite empowering.
There are aspects of the book that confuse me, like the claim that CO2 in the atmosphere is decreasing when my understanding was that pollution is in fact causing CO2 in the air to increase.
The book may not be fantastic (I also noticed lots of errors in it with spelling and writing nose when they meant mouth etc.) but I can't not give it 5 stars for the information it gives that has, as the title suggests, changed my life in some important ways.