The Trinity is the central mystery of the Christian faith. What can we say about the divine nature, and what does it mean to say that God is Father, Son, Holy Spirit, three persons who are one in being? In this book, best selling author Thomas Joseph White, OP, examines the development of early Christian reflection on the Trinity, arguing that essential contributions of Patristic theology are preserved and expanded in the thought of Thomas Aquinas. By focusing on Aquinas' theology of the divine nature as well as his treatment of divine personhood, White explores in depth the mystery of Trinitarian monotheism. The Trinity: On the Nature and Mystery of the One God also engages with influential proposals of modern theologians on major topics such as Trinitarian creation, Incarnation and crucifixion, and presents creative engagements with these topics. Ultimately any theology of the cross is also a theology of the Trinity, and this book seeks to illustrate how the human life, death, and resurrection of Jesus reveal the inner life of God as Trinity.