A young girl and her cat are outside on a dark night when they see a firefly. The night starts to clear and they see stars in the sky. The book then starts to look at natural and artificial light. It introduces vocabulary with bold text and a glossary is included at the back of the book. The text is broken up with diagrams and illustrations. There is a lot of information in the book, but it does not always flow smoothly from one concept to another. It introduces a firefly at the beginning of the book, but does not talk about how a firefly produces light. The book does focus on how light behaves and how we see light. The illustrations complement the text and help further explain the concepts. Overall I think this book is a good introduction for explaining the concepts of light.