The isnād is a list of narrators’ names which precedes an account about Islam’s prophet or his companions, and indicates its origin. The content and the form of this list have been studied in different fields. Islamicists have scrutinised the names contained in the isnād in order to assess the authenticity of the following account and uncover potential fraudsters. Computer scientists, in turn, have focused on form: they attempted to exploit the regular succession of names and transmission terms to develop algorithms capable of distinguishing isnād from non-isnād texts. The present chapter opens a novel horizon by analyzing the structural variations of the isnād within the old and universal context of list-making. A twofold methodology, combining traditional and computational text analysis, highlights the actual contours of the isnād in a large corpus of texts and propose a hierarchy of functions linked to the different variations observed.