[The following essay discusses John Charles Frémont and his wife, Jessie Benton Frémont.]

John Charles Frémont, "The Pathfinder," is generally remembered as a major explorer of the American West and as the conqueror of California. In a career marked by controversy he was one of the first senators elected from California, the first Republican presidential candidate, a mine and railroad developer, a Civil War general, and the governor of the Arizona Territory. His marriage to Jessie Anne Benton, daughter of expansionist Sen. Thomas Hart Benton, gave him access to political power and created a lifelong literary partnership. Donald Jackson and Mary Lee Spence write in their introduction to The Expeditions of John Charles Frémont (1970, 1973, 1984) that "the documentary history of these two persons is but a single subject of study."

John Frémont was the child of a love affair...