Countries differ in their economic success because of their different institutions, the rules influencing how the economy works, and the incentives that motivate people," write Acemoglu and Robinson. Extractive institutions, whether feudalism in medieval Europe or the use of schoolchildren to harvest cotton in contemporary Uzbekistan, transfer wealth from the masses to elites. In contrast, inclusive institutions -- based on property rights, the rule of law, equal provision of public services, and free economic choices -- create incentives for citizens to gain skills, make capital investments, and pursue technological innovation, all of which increase productivity and generate wealth.