Since World War II barriers to international trade in industrial commodities have been reduced while barriers to agricultural commodity trade have become more severe. During the last several decades the world has experienced cycles of "food pessimism" and "food optimism." Nevertheless, as a...

The 1960s through the 1980s were very productive of new theory and empirical insight into the sources of technical change. In this paper I argue that each of the three approaches that have been advanced--induced technical change, evolutionary theory and path dependence--is approaching a dead...