Gr 4-7-- Four more subject-surveys, in a handsome picture series, that will catch youthful imaginations with their wide-ranging selections of fascinating items, beautifully photographed. Topics are developed in two- to four-page groupings, with cross-references and an index--and browsers will find themselves caught and drawn into the flow. Music traces families of instruments and discusses the physics of sound with diagrams and cut-aways. From a 40,000-year-old bone whistle to components of an electric guitar, there are wonderful photos of ancient harps, bagpipes, pianos, and oriental instruments. Shell prods children to think about cases, whether egg, husk, or skull, but deals mostly with mollusks, urchins, and crustaceans. Early Humans shows early human fossils, and pictures selective topics (e.g., art, magic, tools, writing) for the human family up through the Iron Age. Examples come from Africa, Europe, the Americas, early China, the Near East, and Australia. Mammal explores that class in terms of its attributes, evolution, and variety of adapted forms. Photos of the bones of a seal's flipper, an elephant's foot, a panda's jaw, and a close-up of a whale's baleen are sure to appeal to children. While scale is infrequently given, relative sizes of objects are usually clear. A good source for often-asked-for and hard-to-find illustrations, this series could find a place in any library. --Ruth M. McConnell, San Antonio Pub . Lib .