Start with high-confidence african art history books, then narrow by subgenre or adjacent topics.
The African Imagination
F. Abiola Irele
African Art and the Colonial Encounter
Stith Thompson, Sidney Littlefield Kasfir
The Brutish Museums
Dan Hicks
The Ghana Reader
Kwasi Konadu, Clifford C. Campbell
Dust of the Zulu
Louise Meintjes, TJ Lemon
Loot
Barnaby Phillips
The Art of Conversion
Cécile Fromont
African Artists
Phaidon Editors, Joseph L. Underwood
Zulu Beer Vessels
Frank Jolles