The concept of personhood is central to a wide range of contemporary issues, ranging from reproductive rights to the death penalty and euthanasia. We may think that the concept of person is a modern discovery. In fact, however, this idea does not originate with our discovery of human rights, consciousness, and individuality. As this study shows, for example, the fourth-century theologian Gregory of Nyssa developed a very sophisticated concept of the person in the context of his attempts to clarify the paradox of the Trinity - a single God comprising three distinct persons. Turcescu offers the first in-depth analysis of Gregory's writings about the divine persons. Turcescu's work not only contributes to our knowledge of the history of Trinitarian theology but can be helpful to theologians who are dealing with issues in contemporary ethics.