This book is basically a user manual of human mind. When we were born, we weren't giving an user manual to understand how to use the advanced machine, that is, our mind, given to us by god.
I believe this book is the pathway to understanding the working of our brain and try to gain control over it by series of methods over a period of time which I think are very much effective to living a prosperous life.
The thing which really strikes me is, we need to only send good positive thoughts like love, compassion, hope, joy, cooperation, happiness etc to our subconscious mind inorder to make the our way of living better! Its not as easy as it sounds, but we have to practice it from the day we start realizing this fact. And surely we can experience the change!