For more than two centuries, 'E pluribus unum' ('out of many, one') has been featured on America's official government seals and stamped on its currency. But how did America become 'one nation, indivisible'? What unified a growing number of disparate states into the modern country we recognise today? In this monumental history, Simon Winchester addresses these questions, bringing together the breathtaking achievements that helped forge and unify America and the pioneers who have toiled fearlessly to discover, connect, and bond the citizens and geography of the USA from its beginnings. Winchester follows in the footsteps of America's most essential explorers, thinkers, and innovators, including Lewis and Clark and their Corps of Discovery Expedition to the Pacific Coast, the builders of the first transcontinental telegraph, and the powerful civil engineer behind the Interstate Highway System. He treks vast swaths of territory, from Pittsburgh to Portland; Rochester to San Francisco; Truckee to Laramie; Seattle to Anchorage, introducing these fascinating men and others - some familiar, some forgotten, some hardly known - who played a pivotal role in creating today's United States.