Contrary to the classical proposition, the works of Prebisch and Singer launched the
controversial hypothesis of long-term decline in the terms of trade of primary
products vis-à-vis manufactures and a corresponding decline in
the terms of trade of the South vis-à-vis the North. The present
study traces the origin and evolution of the hypothesis and reviews the related
statistical debate. It concludes that the empirical base of the Prebisch-Singer
hypothesis is much stronger than it appeared in earlier decades. Reviewing some of
the North-South models, the study also finds theoretical support for the
Prebisch-Singer hypothesis.