John Henry Patterson

I doubt very much that the chief executives of any of the Fortune 500 corporations can name five edible plants, five native grasses, or five migratory birds within walking distance of their homes, or name the soil series upon which their house sits. And I would contend that if you don't know where you are, you are in fact nowhere at all.

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.