Social capital is important to the efficient functioning of modern economies and is the sine qua non of stable liberal democracy. It constitutes the cultural component of modern societies, which in other respects have been organized since the Enlightenment on the basis of formal institutions, the rule of law, and rationality. Building social capital has typically been seen as a task for second generation economic reform; but unlike economic policies or even economic institutions, social capital cannot be so easily created or shaped by public policy. This paper will define social capital, explore its economic and political functions, as well as its origins, and make some suggestions for how it can be cultivated.