The Thomas Coates papers are mostly correspondence, but they also contain his office files as well as reports about various aspects of the school, essays, articles, sermons delivered in chapel and elsewhere, and devotions. Notable among the sermons was his farewell sermon to the student body on June 5, 1957, entitled The Cloak, the Books, and the Parchments.

In 1945 a number of theologians attended a meeting in Chicago to discuss what were perceived as negative trends in the Lutheran Church--Missouri Synod. The group issued A Statement which was signed by 44 theologians, including Thomas Coates. The office files contain three folders of materials on The Statement of the 44.