International commercial contracts in the context of increasing globalization of the national markets have posed some of the most difficult questions of the legal theory as developed since the emergence of nation states; those are, whether it is possible or desirable to allow international commercial contracts to be governed by the law merchant or, in its medieval name, lex mercatoria, a body of rules which has not been derived from the will of sovereign states, but mainly from transnational trade usages and practices, and to what extent those rules should govern transnational transactions. The traditional approach of legal positivism to the questions maintains that law governing contracts containing a foreign element should be a national law which will be determined according to choice of law rules. However, the particularities of cross border trade yield unsatisfactory results when the rules essentially designed for the settlement of domestic disputes or national laws pertaining to...