SLJ: The history and evolution of travel is introduced to readers through a familiar format in this series. Each book is filled with illustrations that are labeled to indicate the unique features of the machines and that diagram concept is supported by interesting engineering callouts about their designs. In Machines in the Sky and Machines on Land, Barnham goes with a simple-to-complex organizational scheme that brings readers from hot-air balloons to drones, bicycles to mega machines. Machines at Sea notably does a good job describing how complex engineering like hovercraft and hydrofoils work. With the feel of a simplified Stephen Biesty or David Macaulay book, this series delivers a lot of information in a relatively short amount of time, utilizing cutaways, labels, and informational asides to offer a high level of detail despite the somewhat simplified illustrations. VERDICT An additional purchase, but one that’s sure to see good circulation.