Germain Gabriel Grisez (born 1929) is a Catholic moral theologian. Grisez is the author of the three-volume Way of the Lord Jesus. Grisez moves between the spheres of philosophy and theology, articulating a new form of natural law thinking, consonant with the teachings of the Roman Catholic magisterium.^{[citation needed]}

Grisez is emeritus Professor of Christian Ethics at Mount St. Mary's University in Emmitsburg, MD.

Thomas Aquinas, O.P. ( /əˈkwaɪnəs/ ə-KWY-nəs; 1225 – 7 March 1274), also Thomas of Aquin or Aquino, was an Italian Dominican priest of the Roman Catholic Church, and an immensely influential philosopher and theologian in the tradition of scholasticism, known as Doctor Angelicus ([the] Angelic Doctor), Doctor Communis, or Doctor Universalis. "Aquinas" is not a surname, but is a Latin demonym for a resident of Aquino, his place of birth. He was the foremost classical proponent of natural theology, and the father of Thomism. His influence on Western thought is considerable, and much of modern philosophy was conceived as a reaction against, or as an agreement with, his ideas, particularly in the areas of ethics, natural law, metaphysics, and political theory.

Thomas is held in the Catholic Church to be the model teacher for those studying for the priesthood. The works for which he is best-known are the Summa Theologica and the Summa Contra Gentiles. As one of the 33 Doctors of the Church, he is considered the Church's greatest theologian and philosopher. Pope Benedict XV declared: "This (Dominican) Order ... acquired new luster when the Church declared the teaching of Thomas to be her own and that Doctor, honored with the special praises of the Pontiffs, the master and patron of Catholic schools."