The book is an impressive tour-de-force through a great range of topics. Nate Silver discusses forecasting in the areas of political elections, baseball, weather, earthquakes, the economy, infectuous diseases, basketball, climate change, chess, poker, Bayesian theory, war/terrorism...

The insight into each topic is fascinating, and one gem of the book is a step-by-step procedure on using Bayes' theorem to get a confidence estimate for various scenarios, and how to update it based on new observations. I felt that it was a well-done explanation for most readers.

I give the book 5 stars because I liked the topics so much, as well as his insights into them. On the other hand, I should caution that I found two problems with how the book is written:

1. the choice of a target audience is not clear: some passages introduce a topic from scratch, while others assume some advanced knowledge to make any sense at all. I am a scientist and I have played chess and poker and I have watched basketball, so almost all the book was accessible. On the other hand I know nothing about baseball, and I never understood any of the discussion because it assumed familiarity with how player statistics work. When he would give a number, I didn't even know if it had to do with batting, pitching or catching. So that one chapter had reduced impact on me, but I can see people being completely lost in the chess chapter if they don't know the game well. On the other hand, the poker chapter has a complete introduction to the game as if someone did not know it, so that tone is uneven.

2. the writing style jumps around a bit, alternating between colloquial, anecdotal, journalistic, somewhat-scholarly, ... This felt a bit weird as I read the book, although it does not hurt the teaching effectiveness.