Addressed to legal theorists in general, the treatise purports to show that Kelsen's doctrine lends itself to an interpretation according to which the very act of "presupposing" the Grundnorm can be understood as a Grund, i.e. normative source of all positive law; and, what is more, that this interpretation admits of addressing the issue of the (formal) legitimacy of supra-national and directly applicable rules and other norms.