The papers contain business letters of 1899 and 1900, chiefly in the latter year when Stanley McCormick represented the McCormick Harvesting Machine Company at the Paris exposition and corresponded with his Chicago office, his brothers Cyrus Jr. and Harold, their competitor James Deering, and the Company manager in Hamburg, Germany, W.V. Couchman. A few letters and accounts appear relating to his Cimarron Ranch on the historic Maxwell Land Grant in New Mexico, acquired in 1898 with John W. Garrett but later developed by McCormick.
The bulk of the papers deal with the many problems concerning McCormick's care after his breakdown in 1906, and his progressive incapacitation due to a mental disease diagnosed as catatonia. In addition to letters of his wife, members of the McCormick family, and a few friends, correspondence of doctors and psychiatrists such as Frank Billings, Henry Baird Favill, C. G. Jung, Adolf Meyer, and George Tuttle is included, as is a special medical evaluation by August Hoch and Emil Kraepelin. Medical correspondence, reports by nurses and staff, minutes of the board of guardians, financial accounts, and arrangements for his care at the spacious California home provided him are all filed. Four volumes contain court proceedings of 1929-1930 regarding the question of guardianship and his multimillion-dollar estate. Guardians at various times included his wife, Dr. Favill, Cyrus Bentley, Anita McCormick Blaine, Harold Fowler McCormick, and Cyrus McCormick Jr.
