Comparative studies of social policy usually portray the French welfare state as lagging behind most of its counterparts in Western Europe during the first decades of the twentieth century. The sheer complexity of the French system, moreover, with its baroque mixture of separate private, government and quasi-public funds, made it exceptional as well. Yet tardiness and complexity by no means prevented the French from expanding social insurance at an especially rapid clip in the decades following the Second World War. By 1980 France spent more on social security as a percentage of Gross Domestic Product than any country in Europe except Denmark, Sweden and the Netherlands. Today the French are among Europe's most stalwart defenders of publicly funded pensions and health insurance. Given its unimpressive beginnings, how did the French welfare state become such a heavyweight?