The information contained in this book is excellent. However, the author never uses a one syllable word when a longer one is available, and the academic precision of the writing gets in the way of the message. This material is often dense and difficult to understand. If you can, get past the introduction, which needs a translater, into the graphs and heart of the matters. This should have been written in plain language so that those who could most benefit from the information could access it. The rating is for how the information is conveyed, not for the information itself.