By David Macaulay
Two zoo animals keep trying to break out, and each escape plan runs on a simple machine your child works with their own hands.
Sloth is slow and sleepy. Sengi, an elephant shrew, is tiny and fast. The two of them want out of the zoo, and every escape plan they dream up runs on a simple machine. The book turns each attempt into something your child can operate: flaps to lift, tabs to pull, wheels to spin, and a pop-up crane at the finish. Pull one tab and a lever swings up. Spin a wheel and watch a pulley split the load between two ropes. By the end they've tried levers, ramps, wheels and axles, screws, pulleys, and springs, and your child has worked each one by hand. David Macaulay has spent a career explaining machines, and here he does it for younger children with a joke on nearly every page.
This teaches how machines work to a child too young for a thick reference book, by handing them the machine instead of a paragraph about it. A wiggly, hands-on child tends to stay put because there's always another tab to pull, and the sloth-and-shrew slapstick keeps a reluctant reader turning pages for the next gag while the levers and pulleys sink in sideways. One thing to know going in: the flaps and pull-tabs are the whole draw, and with a lot of enthusiastic handling some of them may loosen or tear, so it holds up better as a share-together book than a toss-it-in-the-backpack one. It's the younger companion to Macaulay's The Way Things Work, sized for smaller hands and shorter stretches of attention.