Hilary of Poitiers (d. 367), famous for his role in the Trinitarian debates of the fourth century, was a key figure in the emergence of Western, Latin theology and biblical exegesis. His writings reflect his deep engagement with the major Greek thinkers of his time as well as his distinctive approach to the moral and spiritual meaning of Scripture. His extensive treatment of the Psalms, translated here into English for the first time, is the earliest that survives from the Latin West. The work, which Hilary composed between 364 and his death in 367, reflects his mature theology, comprising an Instructio or introduction, as well as commentary on fifty-seven Psalms (1, 2, 9, 13, 14, 51–69, 91, 119 to 150; LXX numbering) and an extended treatise on Psalm 118. While the Commentaries have received relatively little scholarly attention, they reward close reading. They reflect not only Hilary’s own keen interest in the linguistic and theological features of the biblical text, but also his debts to the traditions of interpretation that were circulating among the pro-Nicene thinkers of his time. Close study of this work reveals how Hilary supplemented his own earlier methods of figurative exegesis by engaging Greek sources, especially the thought of Origen of Alexandria (c. 185–c. 255), and by incorporating insights from his developing pro-Nicene theology. Although Hilary attends to the historical meaning of the Psalms, he regularly views Christ as the true author of the prayers. Thus, the Commentaries are closely linked to his Christological and Trinitarian writings, as well as to his theology of kenosis and deification.