When Britain voted to leave the European Union in 2016, the 48 percent who wanted to stay and the 52 percent who wanted to go each accused the other of stupidity and treason. It is nothing new: ever since the seas separated the British Isles from the continent some 10,000 years ago, it is humans who have decided what geography means. Looking at British history on the grand scale, Ian Morris describes how technology and organization steadily enlarged Britain's arena, but he also explains how the U.K. has been economically overshadowed by America, Europe, and China.