Gregory of Nazianzus, a 4th-century bishop of Constantinople, receives relatively little attention from modern Western scholars, yet he is one of the most influential theologians in the history of Christian doctrine. Many modern Christians understand their religious beliefs through ideas originally expounded by Gregory, yet probably would not recognize his name. As an advocate for the conceptual understanding of the Trinity, Gregory set precedents for the way his fellow and future Christians would perceive and worship God. Holding that Jesus was both fully divine and fully human, Gregory added new complexity to Christianitys grasp of the mysterious relationship between the Son and the Father. He also explored the nature of the Holy Spirit by means of scriptural analysis, both in the Hebrew Scriptures and the New Testament. Gregorys enlightening revelations resonate throughout the varied religious landscape of Christian creed, cult, and code. Christopher A. Beeley examines Gregorys doctrine of the Trinity in the full range of his theological and practical vision of the Christian life. Beeley examines and analyzes Gregorys teachings on the purification, illumination, and limitations of the theologian; the saving work of Christ within the context of Gregorys understanding of salvation; the place of the Holy Spirit in the work of the Trinity; and the Trinitarian purpose of pastoral ministry. This book combines expansive coverage of Gregorys works with meticulous close-readings and analyses to impart new interpretations in the areas of Christology, Pneumatology, and Christian ministry.