In many of the definitions of terms, Mr. Gallant presupposes a basic knowledge of chemistry on the part of his audience. He explains 500 basic concepts briefly, often using diagrams and illustrations, some in color. A list of Nobel Prize winners in chemistry and a periodic table of elements are included. However, the few large charts do not justify the unwieldy size of the book, and for this age group the format is too childish. Of some peripheral value to beginning chemistry students.