Roger Daltrey

I don't think you should ever say, 'This is the last time'. Music isn't like that. You'll be sitting there not wishing to get onto a stage again for maybe two, three, four, five months, or maybe a year, then suddenly you'll wake up and feel like you've got to do it again. It's in the blood, and I never say never.

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.