The article explores how trade and human capital affect a country's wealth. It shows that trade can lead to different living standards between countries, even if they start off the same. Protectionism can help poorer countries. Skilled countries specialize in goods that need skilled workers. Investing in human capital depends on factors like total investments and prices. The model suggests that external effects on human capital come from a lack of information. These effects are local and can't easily move between countries.