This is the fourth of five volumes of Rettig’s translation of St Augustine’s Tractates on the Gospel of St John . In the Tractates , Augustine progressively comments on the Gospel text, amplifying the orthodox doctrinal and moral lessons to be read there. Modern scholars generally concede that Tractates 55-111 fall within a distinct group, thought to have been composed between AD 414 and 420, where Augustine deftly argues for the teaching of Nicene orthodoxy. In Tractate 99 there is a defence of the controversial Filioque . There is also an examination of the paradoxes inherent in the Incarnation: the entrance into history of an immanent and transcendent God the Word; the union of that word with human nature ; how that union, in the Person of Christ, does not confound or diminish either Nature. No less significant is Augustine’s examination of predestination; the mystery of the elect; love of God as the fruit of contemplation; the Eucharist as the source of the martyr’s strength; the divine Nature; and many other notable topics in the discussion of the development of dogma. In these Tractates , Augustine comments upon a discrete portion of the sacred text: the Last Supper and the priestly prayer of Jesus. The reader is left in a state of watch with the Saviour, for his impending Passion, Death and Resurrection, which is discussed in the final volume.