Thomas Smyth was an Irish-born American Presbyterian minister and theologianwho served as pastor of the Second Presbyterian Church in Charleston, South Carolina, for over four decades, authored numerous works defending Presbyterian polity and doctrine, and held to Old School confessional standards while engaging major issues of his day. He also wrote The Unity of the Human Races Proved to Be the Doctrine of Scripture defending monogenism and was a prominent religious figure in the antebellum and Civil War South.