Since the era of Adam Smith economists have been asking, “What creates wealth?” One key answer is specialization and trade. On a timeline of human history, the recent rise in standards of living resembles a hockey stick — flatlining for all of human history and then skyrocketing in just the last few centuries.

As economist Don Boudreaux explains, without specialization and trade, our ancient ancestors only consumed what they could make themselves. How can specialization and trade help explain the astonishing growth of productivity and output in such a short amount of time—after millennia of famine, low life expectancy, and incurable disease?