When Is a Planet Not a Planet?

Elaine Scott's book does more than explain the demotion of Pluto to dwarf planet--it places the evolution of our understanding of the solar system on a historical time line. Pete Larkin's narration is accessible to young listeners. His pace is comfortable--not so fast that youngsters will get lost nor so slow that they'll disengage. The weakness of the production is the sci-fi-sounding musical interludes that introduce "Space Facts"--mini-biographies of scientific pioneers such as Ptolmey and Kepler. These occur often enough to significantly disrupt the flow of the material. The glossary explains the language of astronomers in terms that 7-12-year-old students can understand. N.E.M. (c) AudioFile 2008, Portland, Maine