Authors are commonly thought to have a privileged position when it comes to the interpretation of their texts. Since treaties are consensual instruments, it is not surprising that the parties have a say in the interpretation of their treaties. At the same time, treaties cannot escape what is the fate of every text: the possibility to read a text in the absence of its author is structurally inscribed in it. This chapter examines the ways in which the parties can influence treaty interpretation in various phases of the life of the treaties. It also accounts for the diminishing state authority in the modern practice of treaty interpretation.