This collection consists of the legal and business correspondence of James H. Thompson covering the years 1911 to 1913. The collection is divided into four sections: business which consists of correspondence concerning real estate, The Original Gas Engine Company, stocks and investments; legal matters and politics concerning Thompson's law practice, the election of 1912 and congratulatory letters; personal consisting of correspondence relating to Mason activities, genealogy of Thompson's family and personal favors; miscellaneous and undated material is the fourth section.

Correspondents include Samuel W. Hopkins, O. B. Fuller, John J. Carton, John M. Perry, Alexander J. Groesbeck, Frederick C. Martindale, Dennis E. Alward, Charles E. Townsend, William A. Smith, Grant Fellows, and E. W. Olds.