The book is based upon 4 rules which the author, Paul Mckenna, calls golden rules. There are more than 400 reviews of the book on Amazaon US with a very high percentage of positive reviews.
According to an estimate, more than six million copies have already been sold of the book. It has attracted a larger number of followers in the US, Canada and Europe.
You can buy the book here. I Can Make You Thin®: The Revolutionary System Used by More Than 6 Million People