On their third mission, the AstroNuts visit the Perfect Planet--Earth! Following their failed missions to the Plant Planet and the Water Planet, the lovably goofy band of AstroNuts is sent back in time to prehistoric Earth in hopes of stopping humankind from discovering fire and thus preventing climate change. Zooming off from their top-secret AstroNut headquarters on Mount Rushmore, the animal foursome rocket into a wormhole in their Abe Lincoln Beard Vehicle. When they arrive, the AstroNuts befriend the purple-skinned, fur-clad Sapiens family: Grunk, Lucy, and Baby Urp, who live in a cold, dark home, literally between a rock and a hard place. They soon discover that humans are not the dominant species: Wolves are! A Survival of the Fittest Olympics pits the nefariously cunning wolves against the Sapiens family. Can the AstroNuts help the humans beat the wolves without introducing them to fire? Scieszka's third installment doesn't miss a beat, with its consistent blend of interesting science facts, enthralling collage art, and, of course, a good poop joke or two. Weinberg's illustrations are dazzling, juxtaposing classic works of art with bold color splashes and zany, brightly colored characters. This series has been dependably edifying and entertaining, and this latest volume works fine as a stand-alone, although the recap should entice new readers to visit previous installments. Perfectly fun. (Graphic science fiction hybrid. 8-12) Copyright (c) Kirkus Reviews, used with permission.