To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
I am rather disappointed with the book. It's not the fault of amazon at all but the content and presentation lack the verve expected . Amazon's service was good and I am happy that I purchased the book through you.