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 analyzes reviews to verify trustworthiness.
I received this book today, it was bought as a gift for a birthday present. When I opened it I found greasy finger prints on the front cover of the book! I was not very impressed. I usually find Amazon prime very good but not today.