day and illiterate adults on her own time at night. During this period she developed innovative methods to rapidly teach adults to read and write, based on everyday materials like the Sears catalog. Clark recalls the gross discrepancies that existed between her school and the white school across the street. Clark's school had 132 students and only one other teacher. As the teaching principal, Clark made $35 per week, while the other teacher made $25. Meanwhile, the white school across the street had only three students, and the teacher who worked there received $85 per week. It was her first-hand experience with these inequalities that led Clark to become an active proponent for pay equalization for teachers. In 1919 her pay equalization work brought her into the movement for civil rights. In an interview with Robert Penn Warren for the book Who Speaks for the Negro?, Clark explains how these experiences with her education, as well as her early experiences with growing up in a racist Charleston and teaching in the slums, prompted her to want to work towards civil rights. NAACP involvement Clark first heard of the National Association for the Advancement of Colored People (NAACP) while she was teaching on John's Island from 1916 to 1919. There was no NAACP chapter on John's Island, but a meeting was held in which various preachers came and spoke about what the NAACP was and what exactly it was trying to do. The superintendent was in attendance to collect dues and it was then that she decided to join the organization. In 1918, Clark returned to Charleston to teach sixth grade at Avery Normal Institute, a private academy for black children. She joined the local branch of the NAACP, and she was guided by branch president Edmund Austin in her early political activity. Despite the orders of her principal, Clark led her students around the city, going door-to-door, asking for signatures on a petition to allow black principals at Avery. She got 10,000 signatures in a day, and in 1920 black teachers were permitted. In 1920, Clark enjoyed the first of many legal victories when blacks were given the right to become principals in Charleston's public schools, under the education board of aldermen of Charleston. In 1945, Clark worked with Thurgood Marshall on a case that was about equal pay for white and black teachers led by NAACP in Columbia, South