Butler writes in the biological SF/horror field, and a lot of her work is illuminated by her cultural heritage as an African-American woman. Wild Seed follows the journeys of two almost-immortal creatures, Doro a kind of soul vampire and Anyanwu a shape-shifter, from their origins in Africa thousands of years ago, through the African diaspora, to the Southern States of the US. The imbalance of power between them and their human prey/children reflects some of the experiences of slavery - for example Doro is breeding humans to develop their psychic gifts, as this makes them better meat. His village settlements parallel the slave plantations among which he lives, and the effect on his male victims of having their sexual autonomy and responsibility forcibly taken is a key theme in the chapter I am listening to at the moment.
The premise of the story is almost too fantastic to believe, but the tone is very authentic and tough, so it doesn't fall down. I think it's a good example of a type of American Gothic: southern plantations, decay and bad magic. It's a good reading by an African-American man, called Dion Graham, who does a good range of different southern US voices, and has that calm authenticity that takes you past any reservations.