The central fact in Black Science Fiction – self-consciously so named or not – is an acknowledgement that Apocalypse already happened: that (in PE’s phrase) Armageddon been in effect. Black SF writers – Samuel Delany, Octavia Butler – write about worlds after catastrophic disaster; about the modalities of identity without hope of resolution, where race and nation and neighborhood and family are none of them enough to obviate betrayal…
Mark Sinker, Loving The Alien: Black Science Fiction (1992)