King's participation in the Civil Rights Movement prompted her to co-write essays on women's issues with fellow activist Casey Hayden, most notably "Sex and Caste: A Kind of Memo" (1965), which criticized sexism within the civil rights movement. Sara Evans attributes King and Hayden as founding activists for the women's liberation movement in her book "Personal Politics." Evans claims that King and Hayden used their knowledge of participatory democracy, learned through SNCC membership, to critique women's position in a system of patriarchy. She says their essays stirred the beginning of women's liberation.