These books explore the invention of and benefits offered by two technological devices. Nexi addresses the challenge of developing social robots; Bionic of designing prostheses to incorporate the complexity of emulating the brain-to-nervous-system connection. "Did You Know?" sidebars and illustrations add to accessibility for readers, but babyish book design may deter them. Nexi includes a reading list. Websites. Glos., ind.

JEUTTNER, Bonnie . The Seed Vault . ISBN 978-1-59953-343-8 . LC 2009016567. MOONEY, Carla . Sunscreen for Plants . ISBN 978-1-59953-344-5 . LC 2009015641. WOOG, Adam . The Bionic Hand . ISBN 978-1-59953-341-4 . LC 2009015640. ea vol: 48p. (A Great Idea Series). photos. further reading. glossary. index. Web sites. CIP. Norwood House . 2009. PLB $18.95. Gr 4-6 Each of these titles highlights a specific, and often obscure, invention from the past decade that is making, or has the potential to make, a real difference in the world. With a mix of scientific terminology and accessible sentence structure, the books effectively describe how the ideas took shape and were put into practice by the scientists involved. Students are generally intrigued by robots and will find Nexi Robot of particular interest, though the author is careful to explain the limitations of what this robot currently can and cannot do. Seed Vault explains the need to preserve endangered plant species and how they are collected and protected. Sunscreen for Plants shows how early attempts at protecting crops from overexposure to the sun were either ineffective or somehow harmful to the plant, and how a few individuals worked together to devise a product that was both effective and ecologically sound. Bionic Hand is a fascinating look at how biology and technology are being used to create more useful prostheses for those who have lost a limb. In all of the books, color photographs are included on every page and provide a visual complement to the texts. Small "Did You Know?" boxes appear on nearly every spread and offer up short, interesting facts. Current, relevant Web sites are appended. Librarians looking to beef up science or inventions collections may find these solid additions. Jody Kopple, Shady Hill School, Cambridge, MA