This is a two-volume critical edition of a Middle English commentary on the Psalms based on a Late Version text of the Wycliffite Bible translation. The commentary takes the form of 1,363 shorter and longer glosses, variously interrelated, prepared by scholars sympathetic with the Wycliffite movement, and coordinated carefully with the Psalms text. Its early fifteenth-century base manuscript, MS Bodley 554, was prepared to allow reading and use of the Psalms alongside the best recent and more ancient Latin commentaries, primarily those of Nicholas of Lyra, OFM, and St. Augustine. The glosses are both philological and homiletic, testifying to an avidity at the heart of Wycliffism for the close relationship between textual accuracy in the understanding of Scripture and moral rigor in its application to the concerns of medieval Christian individuals and communities. They display a special interest in understanding the Christian Psalms by way of their Hebrew originals. The edition provides textual notes and variants to parts of the commentary that survive in other Wycliffite Bible manuscripts, the complete Latin sources from Lyra's fourteenth-century Latin text, bibliographic references to the Augustinian sources, and a glossary to the Psalms and commentary texts. There are also extensive explanatory notes concerning the importance of Lyra's exegesis to two other unedited manuscripts related to Wycliffite biblical scholarship: Wyclif's Latin commentary on the entire Bible, the Psalms portion of which is preserved in Oxford, St. John's College MS 171; and a Middle English summary of the Bible in Oxford, Trinity College MS 93.