Alexander Cockburn

England in the late 1940s was famously grim. As I remember it, London back then was a very dirty place, from coal dust and smoke, from the grit stirred up every day by the jackhammers still clearing out rubble from the Blitz.

The historical novelist has to consider what has actually happened, while the SF writer is dealing in possibilities, but they are both in the business of imagining a world unlike our own and yet connected to it.