This is a brief biographical sketch of one of the great leaders of the Scottish Presbyterian Church. Thomas Chalmers (1780-1847) became an outstanding evangelical preacher in the first half of the 19th century. Besides this he was an able mathematician, scientist, social reformer, moral philosopher and theologian. He was a leader of the evangelicals in the years leading up to the 'Disruption' of 1843 when about a third of the ministers and people of the Church of Scotland left the National Church to form the Free Church of Scotland. Previously the Professor of Divinity in Edinburgh University (1828-1843), he became Professor in Theology in the Free Church College up to his passing in 1847. A man of great erudition and piety, his memory should be kept alive as one of the godly 'cloud of witnesses' who call every generation to follow Jesus Christ as they have done in their day.