Frederick Douglass 
Uncle Tom’s Companions: Or, Facts Stranger than Fiction. A Supplement to Uncle Tom’s Cabin: Being Startling Incidents in the Lives of Celebrated Fugitive Slaves [EPUB ebook] 

With the possible exception of Dr. Martin Luther King, Jr., no African American has been more instrumental in the fight for minorities’ civil rights in the United States than Frederick Douglass 1818–1895) , an American social reformer, orator, writer and statesman. His list of accomplishments would be impressive enough even without taking into account the fact that he was born into slavery.

Uncle Tom’s Companions: Or, Facts Stranger than Fiction. A Supplement to Uncle Tom’s Cabin: Being Startling Incidents in the Lives of Celebrated Fugitive Slaves was released following the success of
Uncle Tom’s Cabin. 
  It describes the experiences of a number of slaves, including Frederick Douglass, Josiah Henson, William Wesll Brown, Henry Bibb, and more.