This volume critiques various ways divine simplicity-which suggests God's being is identical to God's attributes-has shaped Christian theology and offers a fresh articulation of the unity of God. The author proposes that the concept of divine simplicity, carried over from the Greek metaphysical tradition, was heedlessly incorporated into the language of Christian trinitarian theology during the patristic period. He identifies numerous problems that have resulted from its retention in postpatristic Christian dogmatics, arguing that uncritical use of the concept renders the biblical God inexpressible and unknowable. This major contribution to contemporary trinitarian dogmatics also contains a unique approach to the problem of Christian-Muslim relations.