These pages are still extraordinary relevant as valuable sources of conceptual clarifications and methodological guidance. Bobbio had the merit not only to draw the boundaries of the different disciplinary approaches to the metalegal reflection on Law, but also to overcome their false opposition together with their mutual isolation. Bobbio invites us to recognize that the Law can be looked at from different points of view - that of justice, that of validity and of effectiveness - corresponding to different disciplines and to as many methods of investigation. He also proposes a still unsurpassed analysis of the secular dispute between juridical positivism and jusnaturalism, illustrating with exemplary clarity the different meanings of the two approaches and the different levels on which their opposition is usually conceived.