Stephen Rea

When you're playing the part of a saxophone or a trumpet player, both of which I have done, it would be nice to be able to play like John Coltrane, but you can't. Your job is to do something else. And I'm not sure what it is, but I don't think I'd be acting Niels Bohr any better if I went and studied physics for five years.

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.