Gibbons deals with theories about the earth's formation, its surface, and its interior. Her explanations of the earth's interior are enlivened by comparisons (magma is like molasses; the thickness of the outer core is about how far it is from New York City to Miami), and her plentiful pictures, with their sharp outlines and broad blocks of color, will help clarify the concepts for the youngest learners. The book closes with an explanation of the three categories of rocks. A good introduction to the planet, though a bit more explanation of how scientists learn about the earth's interior would have been welcome. (Reviewed August 1995)

Gr 1-3--From Pangaea to recycling, Gibbons skims the surface of geology, touching on plate tectonics, volcanoes, earthquakes, and climates. Simple, full-color drawings illustrate the concepts. While some parts of the diagrams are labeled and arrows are used to indicate movement, there aren't enough captions to explain some of the geological processes depicted. Also, two of the three examples of sedimentary rocks, which are defined as ...most of the time...made from fragments of rock that have been stuck together,'' are not made from rock fragments; limestone and chalk are both made primarily from pieces of shell and bone. Joanna Cole's The Magic School Bus Inside the Earth (Scholastic, 1987) provides similar coverage in a livelier package, while individual topics (volcanoes, rocks, etc.) are covered in any number of titles in theNew True Books'' series (Childrens) or in books by Seymour Simon. As an overview, Gibbons's book is an adequate supplemental purchase.--Elaine Fort Weischedel, Turner Free Library, Randolph, MA