How can legal orders coexist? Contemporary lawyers and philosophers frequently accept that a legal system operates under its own terms and is shaped by its own participants. Any problems posed by the plurality of legal orders in the world are to be dealt with by each legal order separately. So persons that are caught in transnational disputes because they are subject to two or more jurisdictions, have recourse to private international law, which is always part of domestic law, i.e. the law where the case happens to arise. But this analysis does not capture international law. This is, or appears to be, a distinct legal order that is certainly not the law of a distinct nation or a people but aspires to cover the whole of the world and – perhaps surprisingly – does seem to meet many of the ordinary criteria of a legal order. This review essay discusses two recent attempts at accommodating international law, Regulating Jurisdictional Relations Between National and International Courts, by Yuval Shany and A Theory of Interpretation of the European Convention of Human Rights, by George Letsas. In their own ways both books outline a ‘substantive’ theory of international law, which is to be welcomed.