Sarah Margaret Fuller (1810-1850), an American feminist, cultural critic, and transcendentalist, fought for equality of the sexes.

Not long after her birth on May 23, 1810, in Cambridgeport, Mass., Margaret Fuller's father started to educate her as a wonder child. She was introduced to Latin at 6 and was reading literary classics when she might still have been playing children's games. By the time she was in her 20s, she could impress such transcendentalist leaders as Ralph Waldo Emerson and Bronson Alcott.

Fuller loved to talk, so she seized on the lyceum as a way to support herself and put forth her ideas. When she ran into masculine protest against a woman speaking to mixed audiences, she developed what she called "conversations." These systematic discussions with some of the most intelligent women in the Boston area were held from 1839 to 1844. Fuller had already begun publishing, but her most significant book, Woman...