In 1532, an empire of roughly ten million people stretched 2,500 miles down the spine of South America — and it ran without writing, money, iron, wheeled carts, or a single horse. Its builders had none of the tools that every other large empire in history depended on. They laid 25,000 miles of engineered road anyway. They turned mountainsides into farmland, kept years of food in stone warehouses, tracked a census on knotted string, and fitted stone blocks so precisely that the walls still stand through earthquakes that flatten everything around them. Written for readers ages 9 to 12, this is the full account: where the Inca came from, how a minor valley kingdom took over a continent's western edge in under a century, what daily life looked like for the farmers and herders and weavers who made it work, and how it came apart when a civil war, an epidemic, and 168 Spanish soldiers arrived within a few years of each other. The book doesn't flatten its subject into heroes and villains. Inca engineers were brilliant; Inca policy forcibly relocated entire communities. Storehouses fed provinces through famine; the labor that filled them wasn't optional. Where historians disagree — about population numbers, about whether knotted cords recorded language, about the early kings — the disagreements are on the page rather than smoothed over. Twenty-five chapters, plus a timeline, glossary, pronunciation guide, and a list of questions nobody has answered yet. Sidebars throughout correct popular myths, profile the people who lived this history, connect Inca practices to Andean communities today, and offer hands-on activities, including instructions for building a working knot-record from string.