Rocks start out as molten magma inside the Earth, and the rock cycle often starts with a volcano. As magma cools and turns solid, igneous rocks are created. As nature wears away at the rocks, bits of sediment drop off. As layers of sediment build up, sedimentary rocks are created. Metamorphic rocks, in contrast, are created through intense heat. Hyde writes in a clear, concise fashion that will also generate interest in every-day uses of rock, whether she is discussing how sedimentary rocks sand and gravel can be mined to make cement and concrete, or how marble, a metamorphic rock, was used to create Michelangelo’s David. This is the most comprehensive book in the “Let’s Rock” series from Crabtree, and should be used as a starting point for other lessons about the types of igneous, sedimentary and metamorphic rocks. There are activities like “Hot or Not,” designed to teach children about crystal formation, and “Mix It Up,” which uses plaster of Paris and sand to create a conglomerate rock. A thirty-seven word glossary provides a solid reference tool. In all, this would be the preferable choice for elementary school classrooms or libraries that need a book about rocks. Reviewer: Elizabeth Leis-Newman