When Elizabeth Cady met Henry B. Stanton in 1839, she was the privileged daughter of a wealthy New York lawyer who was expected to marry well and live quietly and gracefully. Instead, over the objections of her family, she married a passionate abolitionist and entirely changed the trajectory of her life by soon becoming the leader of the nineteenth century woman suffrage movement.

An Uncommon Union offers the first account of Elizabeth Cady Stanton's transformation from debutante to radical reformer by bringing her husband and his family of antebellum social and political...