How British leaders forged alliances to counter the might of Napoleonic France—a coalition made possible by British gold and British industry. When Napoleon seized the reins of power in France, he introduced conscription, and it was a succession of British led and funded coalitions which eventually brought him to his knees. But Britain’s leading role in Europe did not end with Waterloo. Immediately following the Sixth Coalition, and amidst the Seventh Coalition, Britain constructed, with the other great powers, a security system of cooperation and consultation called the ‘Concert of Europe’ that prevented a serious war among them for two generations. Britain’s power to underwrite those coalitions came from a related series of revolutions—agrarian, mercantile, financial, technological, manufacturing, cultural, and political that developed over the proceeding century. For many reasons that happened in Britain and not elsewhere. Of them, cultural values may be most crucial. Constraints were fewer and incentives greater for enterprising Britons to invest, invent, buy, and sell in ways that enriched themselves and their nation more than elsewhere. During the eighteenth century, Britain’s leaders mastered a virtuous power cycle of victorious wars, expanding production, captured territories and markets, and more income. During a speech before Congress in December 1940, President Franklin D. Roosevelt called on Americans to be an ‘arsenal of democracy’ to aid Britain and other countries threatened by the imperialistic fascist powers. Britain played exactly the same role during the Napoleonic era. TheCoalitions Against Napoleon explores how Britain developed and asserted the financial, manufacturing, and military power to achieve that goal.