Robert Charles Sproul was an American theologian, author, Presbyterian pastor and founder of Ligonier Ministries. Sproul was one of the 20th century’s foremost advocates of reformed theology. He was widely read and could engage a range of different secular philosophies with a biblical response. Sproul was an ardent advocate of Calvinism in his many print, audio, and video publications, and he was also known for his advocacy of the Thomistic (classical) approaches to Christian apologetics, less common among Reformed apologists, most of whom prefer presuppositionalism. A dominant theme in many of Sproul’s Renewing Your Mind lessons is the holiness and sovereignty of God.