Naṣīr al-Dīn al-Ṭūsī's Comments on Euclid's Data

This paper is a study of Naṣīr al-Dīn al-Ṭūsī's comments on Euclid's Data. We produce a critical edition, translation and commentary of comments and marginal notes made by al-Ṭūsī in his Revision of the Euclidian text (Taḥrīr kitāb al-Muʿṭayāt li-Uqlīdis). The study results in some insight into what Ṭūsī thought was worth explaining from a mathematical perspective, some information about his manuscript sources, and, perhaps most importantly, some of his scholarly practices in producing his edition of this canonical mathematical text. Another result is that of two versions of this text that can be read in the manuscripts, one can be identified as the more polished draft.