What configuration of institutions and policies is most conducive to human flourishing? The historical and comparative evidence suggests that the answer is social democratic capitalism — a democratic political system, a capitalist economy, good elementary and secondary schooling, a big welfare state, pro-employment public services, and moderate regulation of product and labor markets. Lane Kenworthy shows that this system improves living standards for the least well-off, enhances economic security, and boosts equality of opportunity. And it does so without sacrificing other things we want in a good society, from liberty to economic growth to health and happiness. Its chief practitioners have been the Nordic nations. The Nordics have gone farther than other rich democratic countries in coupling a big welfare state with public services that promote high employment and modest product- and labor-market regulations. Many believe this system isn’t transferable beyond Scandinavia, but Kenworthy shows that social democratic capitalism and its successes can be replicated in other affluent nations, including the United States. Today, the U.S. lags behind other countries in economic security, opportunity, and shared prosperity. If the U.S. expanded existing social programs and added some additional ones, many Americans would have better lives. Kenworthy argues that, despite formidable political obstacles, the U.S. is likely to move toward social democratic capitalism in coming decades. As a country gets richer, he explains, it becomes more willing to spend more in order to safeguard against risk and enhance fairness. He lays out a detailed policy agenda that could alleviate many of America’s problems.