The materials in this collection reflect the entire range of Hauser's activities. It is especially strong in the business and political areas of his career. More than fifty percent of the material is incoming correspondence (1864- 1914). This series forms the basis of the collection (see name index to the correspondence which accompanies this inventory). Hauser's outgoing correspondence is also present, being most complete for the years, 1881-1911. Financial records, legal documents, organizational records and reports support the correspondence series. There are thirty-eight subgroups, including the Hauser estate and Hauser's wife, Ellen Farrar Hauser. The remainder of the subgroups are groups into categories of banking, mining, railroads, land and ranching, and hydro-electric power. Many of the subgroups relate closely to records in the A.M. Holter Papers (MC 80), Montana Power Predecessor Companies Records (MC 268) and others. Banking Subgroups include First National Bank, Fort Benton; First National Bank, Helena; S.T. Hauser and Company, Butte and Virginia City; and Missoula National Bank. Mining Subgroups include Alta Montana Company; Bourbon Mining Company; Helena and Frisco Mining Company/Frisco Consolidated Mining Company; Helena and Livingston Smelting and Reduction Company; Helena Mining and Reduction Company; Helena and Victor Mining Company; George H. Hill's mining interests; Hope Mining Company; Independence Gold Mining Company; Lee Mountain Group; Livingston Coke and Coal Company; Maginnis Mining Company; Meteor Mining Company; Missouri Petroleum and Mining Company; Original Mining Company; Parrot Silver and Copper Company; Rumley Mining Company; and St. Louis and Montana Mining Company. Railroad Subgroups include Helena, Boulder Valley and Butte Railroad Company; Helena and Jefferson County Railroad Company; and Montana, National Park and Ut. Railroad Company. Land, Real Estate, and Ranching Subgroups include Cascade Land Company; Pioneer Cattle Company; Rocky Fork Town and Electric Company; Spokane Ranch Company/Spokane Ranch and Water Company; and Sun River Canal Company. Hydroelectric Power Subgroups include Capital City Power Company; Helena Power Transmission Company; Helena Water and Electric Power Company; Missouri River Power Company; and United Missouri River Power Company.