Award-winning artist David Macaulay introduces readers to his hilarious new creations, Sloth and Sengi, in How Machines Work: Zoo Break! Complete with a unique jacket with an interactive compound machine incorporating several of the simple mechanisms featured in the book, How Machines Work: Zoo Break! uses models and illustrations to demonstrate the technology of six simple machines: levers, pulleys, screws, inclined planes, wedges, and wheels. Follow the mad antics of Sloth and his sidekick Sengi as they try to find their way out of the zoo with the help of machines. Their efforts are brought to life through novelty elements including pop-ups, pull-outs, and lift-the-flaps, allowing readers to explore in greater depth how and why machines work. Spreads highlight the use of simple machines in everyday objects, such as scissors and clocks, mixers and whisks, bikes and brakes, while the story contains clear and simple text to engage the reader.