Amazon calculates a product’s star ratings based on a machine learned model instead of a raw data average. The model takes into account factors including the age of a rating, whether the ratings are from verified purchasers, and factors that establish reviewer trustworthiness.
This is a lively introduction to Rust. The writing is friendly to beginners, or so it seems to me, because I am not a beginner, so I'm guessing a little. For a more experienced developer, it might be a little too watered down and informal, but I'm not complaining. You have the Rust website as an alternate source of information. You could come to this book after learning Python.