Who is Frederick Douglass from The Fiery Trial: Abraham Lincoln and American Slavery and what is their importance?

Abolitionist, Frederick Douglass, looked to Lincoln as a strong supporter of his cause. While Lincoln was in the White House, he and Douglass met on several occasions to discuss slavery and the rights of the black man. Douglass encouraged Lincoln to allow blacks to join the military, and after the Emancipation Proclamation, they met to discuss ways in which to spread word of the act.