Book excerpt: This paper examines how country, industry and firm characteristics interact in general equilibrium to determine nations' responses to trade liberalization. When firms possess heterogeneous productivity, countries differ in relative factor abundance and industries vary in factor intensity, falling trade costs induce reallocations of resources both within and across industries and countries. These reallocations generate substantial job turnover in all sectors, spur relatively more creative destruction in comparative advantage industries than comparative disadvantage industries, and magnify ex ante comparative advantage to create additional welfare gains from trade. The relative ascendance of high-productivity firms within industries boosts aggregate productivity and drives down consumer prices. In contrast with the neoclassical model, these price declines dampen and can even reverse the real wage losses of scarce factors as countries liberalize.