Rev. Dennis Joseph Billy, C.Ss.R., D.Theol., S.T.D. is a Roman Catholic priest of the Redemptorist order (Congregation of the Most Holy Redeemer, Latin: Congregatio Sanctissimi Redemptoris C.Ss.R) and has been Professor of the History of Moral Theology and Christian Spirituality at the Accademia Alfonsiana of The Pontifical Lateran University in Rome, Karl Rahner Professor of Catholic Theology at the Graduate Theological Foundation and John Cardinal Krol Chair of Moral Theology at St. Charles Borromeo Semininary.