The so-called Lectura Thomasina, a commentary on Peter Lombard's Sentences, was composed by the Dominican William of Peter of Godin at the beginning of the 14th century. The manuscript tradition provides the text with the title 'Thomasina' because of the large number of verbatim quotations from Aquinas' writings. This text is not a mere compilation of Aquinas' dicta, but represents an attempt to outline the fundamental elements of Thomas' doctrine, giving them both unity and coherence. For this reason, Godin's commentary is an important witness to the reception of Aquinas' texts during the period between his death and his canonization. The critical edition of the Lectura Thomasina, presented here for the first time, is based on an examination of the entire manuscript tradition and is accompanied by an historical and philological introduction. In this part of his Sentences commentary (prologue and book I, distinctions 1-27), Godin deals with some central themes of scholastic theology, such as the scientific nature of theology, the knowledge of God, divine attributes, the doctrine of the Trinity, divine relations, the doctrine of caritas, the omnipotence of God, and the predication of God's names. In addition to these theological questions, the text contains a philosophical digression in distinction 8, where Godin examines the distinction between essence and existence both in God and in created beings.