This book is about moving money within and across countries. It raises the following question: are the few percentage points of my income that I save each month lent to a firm in my neighborhood or do they end up refinancing the short-term debt of the Republic of Mali instead? The answer to this question does not depend on technology, for, since the telegraph was invented, money has had the capacity to move to almost any urban area in the world at the speed of electromagnetic waves. Nor is the answer more likely to be found in economic reasoning. The local firm and the foreign government, holding risk constant, will pay the same interest on the sums they borrow. The answer, instead, is political. My savings are more likely to help fund production in my local industrial district if I live in Germany, Italy, Canada, or the United States, but to end up in Timbuktu if I live in Britain or France. Mobility of capital reflects the degree of centralization of the state. It is the structure of the state that determines the outreach of the “great go-between,” Bagehot's phrase for Britain's financial system, to which he ascribed the responsibility for moving money.