Overall, I would give this book 4 out of 5 stars. Even though this book has encyclopedia in the title, it is nothing like any other encyclopedia I have seen. This is because of how it gives great explanations paired with great pictures adding to what it says in the book. My favorite part of the book was the pages about the different kinds of radiation, and their usefulness in our lives (and astronomy). I liked this because it told you how long the frequencies of each kind of radiation was with higher frequency types of radiation having wavelengths that could be smaller than atoms. I also liked the pages that talked about gravity, and how a black hole has gravity so strong not even light can escape after entering its event horizon. This made me think about all the different kinds of astronomy in the world, and how destructive black holes could be. Even though I like this book very much, it wasn't perfect. This was because I felt some pages, like the ones describing the planets in the solar system, cold be condensed into smaller pieces of info. Other pages had so little writing it left out very important details. If there was another edition of this book, I wish it would have almost equal paragraph sizes per page. oOverall, I liked this book, and would recommend it to people who have any interest in astronomy, and even physics.