Join the Energy Force and save the planet by learning about sustainable energy. TreeTops inFact is an exciting non-fiction series for children aged 711. Its range of subjects and careful levelling make it easy to select books that children will love. Generation Energy enrols the reader in the Energy Force - a team of agents dedicated to spreading the word about sustainable energy and looking after the planet. TreeTops inFact is a non-fiction series that aims to engage children in reading for pleasure as powerfully as fiction does. The variety of topics means there are books to interest every child in this compelling series. The series is written by top children's authors and subject experts. The books are carefully levelled, making it easy to match every child to the right book.