Toni Morrison has helped African-Americans identify and embrace the both the "African" and "American" portions of their heritage in a way that few other writers have been able to do. She does not shy away from either the negative or the positive of either culture.  For example, in "Beloved," Morrison elucidates the lasting psychological impact of slavery; in "Jazz" she celebrates the unique contributions of African-Americans to American culture; in "The Bluest Eye," Morrison acknowledges the social pressure of conformity. 

There are a couple of books out there that can help you understand Morrison's influence on African-American culture.  One is:  Religiosity, Cosmology and Folklore : The African Influence in the Novels of Toni Morrison  by Therese E. Higgins.  Another is "Toni Morrison's Fiction:  Contemporary Criticism by D. Middleton