How many stars was this book rated?
When you are looking for book reviews, stars are just one method that reviewers can use to rate a book. When a person reviews a book, they can pick whatever rating system they want--it can be stars, thumbs-ups, smiley faces, a 1 to 10 scale...if they can think of it, they can use it. Every website and newspaper is unique in how they choose to rate reviews.
If you are looking for a review for a particular book, I recommend doing a search. When doing an internet search, how you type in the search terms can help or hurt your results. I recommend typing in Charlie AND book reviews. That will help to narrow the results. It will also help if you type in the author--Charlie by (author name) AND book reviews. From there, you can hopefully find some reviews. If it is an older book, it will be harder to find reviews. Another thing to look out for is the difference between reader or user reviews, and actual reviews from paid professionals. Try to use only reviews from websites that are newspapers or journals; those institutions hire and pay people to do official book reviews, and they are more experienced and thorough in their reports.
I hope that those thoughts helped to get you started; good luck!