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 the five-star definitive biography of a brilliant, confident, enigmatic and multi-faceted leader told magnificently. James MacGregor Burns' thoroughly researched two-volume tome comes alive to any reader. If you desire to know Roosevelt and the America and world of this age, read it.