From the patristic period until today, John’s Gospel has served as a major source for the church’s knowledge, doctrine and worship of the triune God. Among all New Testament documents the Fourth Gospel provides not only the most raw material for the doctrine of the Trinity, but also the most highly developed patterns of reflection on this material–particularly patterns that seek to account in some way for the distinct personhood and divinity of Father, Son and Spirit without compromising the unity of God. While there have been recent, fine studies on aspects of John’s doctrine of God, it is surprising that none summarizes and synthasizes what John has to say about God as Father, Son, and Holy Spirit. In order to fill this gap, Koestenberger and Swain offer a fresh examination of John’s trinitarian vision in this New Studies in Biblical Theology volume. Part One situates John’s trinitarian teaching within the context of Second Temple Jewish monotheism. Part Two examines the Gospel narrative in order to trace the characterization of God as Father, Son and Spirit, followed by a brief synthesis. Part Three deals more fully with major trinitarian themes in the Fourth Gospel, including its account of Jesus Christ, the Holy Spirit, and mission. A final chapter discusses the significance of John’s Gospel for the church’s doctrine of the Trinity, and a brief conclusion summarizes some practical implications. Addressing key issues in biblical theology, the works comprising New Studies in Biblical Theology are creative attempts to help Christians better understand their Bibles. The NSBT series is edited by D. A. Carson, aiming to simultaneously instruct and to edify, to interact with current scholarship and to point the way ahead.