Our library is organized by subject, using the Library of Congress Classification system. African American history is a broad subject, meaning you may find relevant books through the library. However, two call number ranges that may be particularly helpful are:
E184-E185: African American history
E441-E453: Slavery
When searching a database of books (think: OneSearch, Google Books, or WorldCat):
Also, look for Library of Congress Subject Headings with those terms. A few useful subject headings for this project:
African Americans -- History -- Sources
Slave narratives -- United States
United States -- History -- Civil War, 1861-1865 -- African Americans
United States – History – Colonial period, ca. 1600–1775 – Sources