Gr 4-6 This book could have been useful as a sort of reference picture dictionary of prehistoric life. Its scope is its best selling point; it covers not only dinosaurs and early mammals, but also invertebrates and early plants. However the information given is brief (usually two or three sen tences), the slant is British, and all mea surements are metric. The illustrations are flat and ineptly drawn, giving one the im pression that the book is actually a hasty paste-up job of educational bubble gum cards (a theory supported by some of the illustrations' captions, which actually state ``See next card''). All of this could be overlooked, however, if only the book had an index. As it is, readers have to page through the whole thing just to track down one entry. For better field guides to pre history, try Benton's The Dinosaur Ency clopedia (Messner, 1984) or Diagram Group's Field Guide to Dinosaurs (Avon, 1983). Cathryn A. Camper, Minneapolis Public Lib .