Add to ORKGThe bulk of international commerce consists of trade in intermediate goods, raw materials, and goods which require further local processing before reaching the final consumer. Although this has become a common observation, it has yet to receive central attention in the pure theory of international trade. A further observation is that few items in international trade are pure raw materials or primary factors which have not received any value-added from other local inputs. Put together, these remarks suggest that in the typical productive spectrum whereby primary factors and labor help produce and transform commodities into the final state required by consumers, international trade takes place in "middle products". The purpose of this article...