Roy Barnes

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.

Many of Judy Blume's books - which I devoured when I was growing up and where I found characters that were believable because they were a lot like me - caused considerable consternation when they were first published, but now they're widely accepted as an essential part of the children's literary canon.