Some of humanity’s mightiest engineering achievements are small in scale—and, without them, the complex machinery on which our modern world runs would not exist. In Nuts and Bolts, structural engineer Roma Agrawal examines seven of these extraordinary elements: the nail, the wheel, the spring, the magnet, the lens, the string, and the pump. Tracing the evolution from Egyptian nails to modern skyscrapers, and Neanderthal string to musical instruments, Agrawal shows us how even our most sophisticated items are built on the foundations of these ancient and fundamental breakthroughs. She explores an array of intricate technologies—dishwashers, spacesuits, microscopes, suspension bridges, breast pumps—making surprising connections, explaining how they work, and using her own hand-drawn illustrations to bring complex principles to life. Alongside deeply personal experiences, she recounts the stories of remarkable—and often uncredited—scientists, engineers, and innovators from all over the world, and explores the indelible impact these creators and their creations had on society. In preindustrial Britain, nails were so precious that their export to the colonies was banned—and women were among the most industrious nail makers. The washing machine displayed at an industrial fair in Chicago in 1898 was the only machine featured that was designed by a woman. The history of the wheel, meanwhile, starts with pottery, and takes us to India’s independence movement, where making clothes using a spinning wheel was an act of civil disobedience. Eye-opening and engaging, Nuts and Bolts reveals the hidden building blocks of our modern world, and shows how engineering has fundamentally changed the way we live.