Did you know there are four main types of volcanoes? Or that volcanoes are classified as active, dormant, or extinct? The Devil's Tower in Wyoming is an extinct volcano. It's about 40.5 million years old! Gail Gibbons explores the hows and whys of volcanoes, using direct sentences, maps, infographics, and illustrations. Readers will learn about the four layers of the earth, the basics of plate tectonics, the different types of volcanoes, and much more. Fully vetted by a working volcanologist, this book is perfect for earth science lovers and aspiring volcanologists.