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 synthesizes what John has to say about God as Father, Son, and Holy Spirit. In order to fill this gap, Kostenberger and Swain offer a fresh examination of John's trinitarian vision.