Sylvia Mathews Burwell

Between 1939 and 1945 you produced weapons and war equipment valued at thirteen billion dollars, 70 per cent of which you shipped to your allies. The same process is going on today in Canada's much larger and growing industry.

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.