There are over 6,000 accounts in existence from slaves and ex-slaves. About half come from before the Civil War and about half after the war. African American scholars began to gather stories from blacks who lived around historically black institutions, but the bulk of the narratives came from the Works Progress Administration project in the 1930's. John Blassingame’s 1972 Slave Community used these narratives. George Rawrick placed these narratives in 40 volumes between 1972-1979.
The slave narratives are best source we have to study enslaved Americans. No group of bond people in the world has left such a record of their bondage. They provide a balance to the distortions of slavery by white scholars in the post-slavery era.
All historical sources have problems, but black sources seem to have their legitimacy questioned more than white.
The narratives do present a set of issues, and they need to be noted when studying:
Post-war narrative problems
Ante-bellum narrative problems