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.
In order to use this book you have to have a working version of Microsoft Windows 7. This means I would have to buy a licence. I don't like the idea of buying a book and then find out I need to spend another $10 - $15 dollars to be able to use it.