International economic law is a convenient term to cover mainly the multitude of bilateral and multilateral treaties made since the Second World War on trade, commerce and investment. That does not mean that it is a new subject. There are numerous bilateral treaties on trade from earlier centuries, an Anglo/Portuguese treaty of 1353 providing for mercantile intercourse. In the nineteenth and twentieth centuries there were many treaties on trade, customs, establishment and navigation. The last fifty years has seen important multilateral treaty-making in these areas and the conclusion of numerous bilateral investment treaties (BITs). A detailed description of the various new international and regional economic organisations is beyond the scope of this chapter. One can give only a brief overview of the subject, principally BITs and the WTO and similar organisations, concentrating more on the settlement of economic disputes. Dispute settlement in general is dealt with in Chapter 22 below.

Most countries that achieved their independence after the Second World War were developing, and most remain so. During the colonial era, the imperial powers controlled trade and investment between their colonies and themselves and third states. With independence, the new states could have more control over trade and the activities of foreign investors, but they also needed to encourage foreign investment.