In the Venture series, a close look at invertebrates, which comprise more than 95% of all animal species. Intended for teens who want ``advanced information,'' the book has the readability of an encyclopedia but lacks an organizing overview and adequate illustrations and suffers from a limited glossary and index. A standard science encyclopedia (e.g., Grolier's The New Book of Popular Science) provides more information, with better organization and graphics. Some of the information here is incomplete: in discussing sponges, Aaseng describes two forms of asexual reproduction but ignores sexual reproduction. In the glossary, ``ossicles'' are defined as ``small hard nodules of calcium carbonate'' and ``spicules'' as ``long sharp supportive structures.'' According to the text, ossicles, too, are supportive structures, while spicules come in ``a variety of shapes.'' Aaseng notes that most biologists class Protozoa in their own kingdom, ``Protista,'' which appears in neither glossary nor index. Not a first choice. (Nonfiction. 12-14)
