Ago, Roberto Keywords: Vienna Convention on the Law of Treaties (Vienna, 23 May 1969) | Mots clefs: Convention de Vienne sur le droit des traités (Vienne, 23 mai 1969) | ABSTRACT In his introduction to the Law of treaties in the Light of Vienna Convention, Roberto Ago presents a preparatory work of the International Law Commission and the different steps of the Vienna Convention. He then analyzes the incidences of political antagonisms on the conference, and later the confrontation of interests between the old and the new Sta…