Guns, Germs, and Steel
For the read time (11~15 hours) it's a 3.5-star book.
It shows a really well-based opinion for a Eurocentric modern world focusing on how environment has shaped cultures. The only reason it's not a 4- or 5-star book is because the book is tiresome to read. I don't see some parts from the 1st and 2nd books as really necessary. It only reinforces the same situation in different contexts, which is good but makes the read boring sometimes.
I also think Guns, Germs and Steel is a really poor name considering what the book focuses on, the real name could be: Geography and domestication of animals and plants. Guns, germs and steel are all results of other complex environmental situations, which the book really focuses on. The book as a whole doesn't go deep directly on those subjects.
A last tip which could make the whole book more pleasurable is to read it with an atlas around, it should be really useful (mainly when you don't have a great Geography background).