If you check your local library, you’ll probably find a couple of different multibook sets about simple machines. Each set typically devotes one title to each of the six simple machines. Some of the sets do little more than list examples of specific simple machines; others are written for fluent readers with good multiplication skills. This set strikes a nice balance. The simple, straightforward text is divided into short chapters, with a large photograph on every page to help clarify the activities and concepts. The other titles in this series are Inclined Planes and Wedges, Levers, Pulleys, Screws, and Work.