Gr 7-10 A comprehensive overview of DNA: what it is, what it does, and how it functions. The book begins with a simple explanation of basic DNA structure, and becomes more technical as the information becomes more intricate. The composition of the DNA ladder is explained in detail, followed by discussion of how the sequences split and combine to form various patterns. Transcription and translation of the message into the formation of proteins is examined, including the roles of the various forms of RNA. Mutations of the DNA strand and the resultant genetic disorders are touched upon, as are instructions for making DNA models. In all, the material is presented in a logical sequence, and is quite understandable if readers are willing to put some effort into interpreting the vast amount of information offered. Numerous diagrams accompany the text, mostly letter chain representations of the DNA strands, plus a few black-and-white line drawings and photographs, most of which are helpful. While this book is not for average readers, it would be useful for students with an interest in the subject, and would be a good complement to the variety of titles on genetics currently available. Denise L. Moll, Lone Pine Elementary School, West Bloomfield, Mich.