Jared Diamond wrote Guns, Germs, and Steel as an answer to what he called Yali’s question: how did the rich nations turn out be Europe rather than, say, the islands of the South Pacific?

Russ Roberts wants to know how it is that the cross-country gaps in wealth persist. In the latest econtalk audio file, he presses Nobel Laureate Robert Lucas with this question in a number of ways. For example, he asks Lucas why an uneducated Mexican can earn more in Chicago than in Mexico.

One point that Lucas makes is that a lot of the escape from poverty consists of leaving primitive farms for the city. It’s an interesting, wide-ranging interview.