Many of the archives of Missouri have collections of published biographical information. The public libraries in St. Louis and Kansas City also have good collections. Also search the biographical sections of statewide, regional, and county histories.
The Family History Library has a large collection of biographical sources. Selected volumes are on Family History Library films 1000272-79, including Howard Louis Conrad, Encyclopedia of the History of Missouri, a Compendium of History and Biography for Ready Reference (New York, New York: Southern History Company, 1901; Family History Library book 977.8 H2c; films 1000272-73; fiche 6051492).