3.75 stars. As much as I liked the natural history facts, I must say I have couple of criticisms:
1. The illustrations. They were crude and all seemed to look alike. Illustrations in reference books should be as life-like and detailed as possible in my opinion, as they're there for visual learning, not for display of art.
2. Very few animals had their size in their description. Knowing animal's size attributes enormously to visualizing how they looked like in real life. It's an important fact (especially when it comes to dinosaurs), and after a while they could all been either size of a football or a plane, it all blended together.
Having said all that, it was still an interesting read, especially stories about finding the fossils.