This paper explores the theory of transnational law. It is proposed that transnational civil regimes transcend the public-private distinction both in the substantive (private vs public law) and the procedural (public vs private regulators) dimensions. A toolbox of twelve generic governance mechanisms is introduced, which in the institutional organization of cross-border commerce are recombined into effective regimes. It is suggested that the resulting institutional innovations cannot appropriately be described by traditional concepts of the relation of state law and private ordering (delegation, deference, and incorporation), but should rightly be perceived as a ‘legal mutation.’