William Edward Burghardt "W.E.B." DuBois (1868-1963), is one of the most renowned advocates of race equality and education of African Americans in the early 20th century. He was Harvard-educated, a sociologist, journalist and teacher. Du Bois was a prolific author and activist. One of his best known works is The Souls of Black Folk, a series of essays on social, political, and economic equality among the races. He was a co-founder of the National Association for the Advancement of Colored People (NAACP).
Several books and essays written by W.E.B. Du Bois are available through Project Gutenberg. Among the available titles are:
Darkwater: Voices from with the Veil
The Negro
The Negro Problem
The Upward Path: A Reader for Colored Children
The Suppression of the African Slave Trade to the United States of America
The Conservation of Races
The Quest of the Silver Fleece
The Negro in the South
The Harlem Renaissance by 
The New Negro: Voices of the Harlem Renaissance by 