Interacting with theologians throughout the ages, Riches narrates the development of the church’s doctrine of Christ as an increasingly profound realization that the depth of the difference between the human being and God is realized, in fact, only in the perfect union of divinity and humanity in the one Christ. He sets the apostolic proclamation in its historical, theological, philosophical, and mystical context, showing that, as the starting point of "orthodoxy," it forecloses every theological attempt to divide or reduce the "one Lord Jesus Christ."