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.
As the title says book is cool but the way it was shipped to me was really bad - it came all over US in single layered plastic bag with holes - no padding or extra cover on the book to protect it so when it arrived the book was dirty and looked like that it was used before. I had it as a present for my friend, so I couldn't return it as there was not enough time to get replacement or similar book. The book was sold by Your Online Bookstore, I never had problems with books delivered directly by Amazon.