It's often hidden underground, but soil is a complex mixture of rock, organic matter, gases, and water. Soil forms very slowly and is made up of several layers—which readers can learn all about in this book! In the main text, they uncover the many different types of soils, each of which play a crucial role in the lives of many living things on Earth. Eye-catching graphics, age-appropriate text, and helpful diagrams combine to make for an excellent reading experience. Readers put their knowledge to the test at the end with a quiz.