This book is a must. Why? As a grandfather, I have the privilege of watching my grandchildren grow up and develop interest in the world around them. I have one who is lover of snakes, alligators, and of course dinosaurs. He is five and he is good. We have watched every documentary on Netflix, YouTube, and Amazon Prime that has been produced. I am tested every time we get together and we are headed to Indianapolis next week. I am ashamed to admit that I have only passed one test, and that was a 60, 6 out of 10. The names, when they lived, and whether they are a meat or plant eater are all required. This book helped me pass my only test and is a must read every time we meet. So, if you want to do a quick study, this encyclopedia is a must