Gr 4–6—Each of these well-designed volumes does a commendable job of introducing its respective subject. The facts are clearly explained and punctuated by interesting sidebars and photographs that reinforce the various concepts. The books include "Eco Notes," brain teasers, and simple experiments. The series promises a "media enhanced" Web-based component. By entering a unique code on the publisher's website, readers should have access to audio, video, embedded Web links, activities, quizzes, and slideshows. However, the books can certainly stand alone.