For much of the early part of the twentieth century, political theorists debated the moral and economic merits of capitalism in competition with communism. With the collapse of the Soviet Union and its satellites, and the triumph of the market economy, those on the political left briefly flirted with the idea of market socialism. But critics of capitalism are running out of alternative ideas, to the point that a placard at an anti-capitalism march proclaimed ‘Replace Capitalism with Something Nice!’. Are we stuck with capitalism? How far can it be modified? How far should it be modified?