Although probably for many readers I have overdone the details of the scientific theories or experiments explained in the books, but my desire is that they understand that it is not just my opinion or experience on the subject but a body of research from many parts of the world that has come to these conclusions. The exercises are an essential part of the books because without practice it is difficult to change your life, and that is what these books are about changing your life to have more joy and happiness. I have added some key personal experiences that influenced my life and hope that the readers see that I know some of the feelings and problems that they have. If I could overcome them then just about anyone can, because I am not some special genius. I have included some charts and picture to break up the monotony of my writing and clarify some points, which I hope is worthwhile for the reader.