De scientia Dei (On God's Knowledge) is one of the few major texts by John Wyclif that has not already been published. According to John A. Robson, the De scientia Dei is 'in some way, the most important of all the treatises' of Wyclif's so-called Summa de ente. It was probably written in 1372, when the editorial project of the Summa de ente was in its final stages, and when Wyclif was at the peak of his academic career. In it he deals with God's knowledge as a divine attribute, presents his peculiar view of God's knowledge as a relation of reason, distinguishes between God's knowledge of creatures in their intelligible being and in their actual existence, and argues in favour of a compatibilism between God's foreknowledge of future events and the liberty of human will. In this connection, a long section is also devoted to questions about the doctrine of salvation, and to the first elaborated exposition of Wyclif's doctrine of grace. The edition is preceded by a historical and doctrinal introduction, enabling the reader to situate the tract within the framework of Wyclif's own production and to appreciate the relevance of some of the topics faced in the text in the light of the development of Wyclif's theological and philosophical thought.