Cole and Degen have struck at the core once again to produce an exciting, attractive, and informative science book for young readers. Children who entered Ms. Frizzle's classroom in The Magic School Bus at the Waterworks (Scholastic, 1986), are in for another exhuberant, intriguing field trip. This time, it's to the center of the earth. Surprises abound through each strata down to the very inner core where it is hot, hot, hot. The class collects rock samples before the bus is expelled from the earth's core in a volcanic eruption. Illustrations are in watercolor cartoon format and attendant ``balloons'' contain pertinent information or students' humorous asides. There are also pages from students' reports on rocks. A tongue-in-cheek section at the end discusses the real and fantasy aspects of the book. Containing uncluttered text and illustrations, it is an anticipatory page-turner full of exciting adventure from school yard to volcano and back. Mary Lou Budd, Milford South Elementary School, Ohio Copyright 1988 Reed Business Information, Inc.