In this third and final gallery of prehistoric creatures (the authors have announced that they’ll be delving into mythology next), the “titanic pterosaur” quetzalcoatlus unfolds huge wings, saber-toothed smilodon lazily stretches out massively clawed paws, a glowering mastodon lunges headfirst toward the viewer and an array of other therapsids, early mammals, birds and insects lurk beneath layered flaps filled top to bottom with melodramatic captions and startling facts. As before, the art’s slashing brushwork leaves the smaller figures and details more impressionistic than exact, but the paper engineering is consistently inventive and exciting—even fairly durable, so long as leaves and flaps are opened and closed slowly. The fur-clad cave painter beneath the final flap introduces the scariest predator of all, and provides an appropriate cap for this rousing, deservedly popular series. (Novelty/nonfiction. All ages)