Grade 5 Up-These oversized volumes are attractive, but not very useful for those with no background in the subjects. They are both topically arranged on double-page spreads full of full-color photos, diagrams, and drawings. However, they lack significant features that one generally associates with a "dictionary"-definitions, pronunciations, and alphabetical order. Measurements are given only in the English system. Earth effectively shows different map projections, but none of the examples of sedimentary rocks have visible layering; on the cave page there is nothing to help readers visualize how cave formations grow, and there are some errors in the depiction of "Evolution of the Earth." Donald M. Silver"s Earth makes good use of drawings to present a more comprehensible picture. Universe"s drawings and diagrams mislead by both omission and commission. For each planet, bar graphs show atmospheric composition with no hint of density, so that readers get the impression that Venus"s...