I don't want to steer anyone away from this book. It's a 3+, really. It's interesting, it's well-written, but it's shorter than I'd expected and doesn't really hang together as a book. Each one, as an article/essay/blog post would have been very interesting, but I expect more ambition in a book, I want it to sweep me away (even nonfiction) and tell an interesting story from start to finish. And there was no start to finish here, just essay, essay, essay, etc., each one good, but the sum < parts.
It was kind of perfect for bedtime reading, one chapter per night. It's definitely not a history of games: it's a look at how our minds work with regard to game dynamics (and hence how designers might think about approach their games, given how humans are). Good stuff, and I learned things, but I won't be fondly recalling the book two years from now--I'll just wonder where I learned that stuff and shrug.
(Note: 5 stars = amazing, wonderful, 4 = very good book, 3 = decent read, 2 = disappointing, 1 = awful, just awful. I'm fairly good at picking for myself so end up with a lot of 4s).