World merchandise exports amounted to 5.3 trillion us dollars in 1997 and exports of commercial services amounted to 1.3 trillion. These are unpecedented volumes that have expanded much faster than income in the post-war period. More than half of the volume of merchandise trade flows amongst...

In this paper, the author will try to describe in this lecture what economists know about foreign trade and in what ways their understanding has improved as a result of the last twenty years of research.