Iain M. Banks’s The Hydrogen Sonata explores the background of the far-future Culture, where human, alien, and mechanical sentient beings mingle in a galactic melting pot.

What concerns were on your mind when you created the Culture 25 years ago?

The main one was providing a kind of moral background for Zakalwe in Use of Weapons; I wanted this tragic, ruthless, sentimental, multiply flawed character to be working for the demonstrably good guys, and the Culture grew around that requirement. It was a process waiting to happen as my various reactions to the SF stories I’d read started to coalesce into something more coherent. Only this wasn’t 25 years ago, this was nearly 40 years back; the first draft of Use of Weapons was written in 1974, when I was 20. I’d read stacks of SF and while I loved the genre, I had the standard reaction of anybody ambitious within their chosen field: while everything that had gone before was perfectly good and sometimes brilliant, there was something missing that only I could bring to the party. I was young, ambitious, and untroubled by self-doubt. Then the madly overcomplicated first drafts of my early Culture novels got turned down, and I turned to mainstream, writing The Wasp Factory in 1981, in an attempt to, if nothing else, get rejection slips from a wider spread of publishers.

Why do you think the Culture has continued to be so popular with readers?

Luck? Sometimes I think I just stumbled across a rich seam of possibility that had gone under-exploited by others—but access to which had been opened up by them—and I’ve been hacking away at it ever since. I guess it’s providing an imaginative space readers can inhabit that’s appreciably different from that offered by other writers. An analogous thing goes on for me, of course; it gives me an environment to develop ideas within, and the initial concept was encompassing enough—or maybe just vague enough—to accommodate pretty much anything. I still have stuff that I want to try out in this giant train set of a fictive universe.

What are the advantages and disadvantages of writing space opera today?

It offers the broadest of canvases to work on, and there’s an implicit license you get with it that allows almost any flight of imagination, so it’s always going to attract writers and readers who want a degree of scientific and psychological realism, but, well, not too much. You have to get the tone right—neither overly earnest or too tongue-in-cheek—but then getting the tone right applies to all literature.

Speaking of tone, you put a lot of deadpan humor into your books.

Well, there’s humor almost everywhere, so why should SF or space opera escape? In the end it’s about balance; you want to produce that sense of wonder SF is uniquely good at creating, and you want to dazzle the reader with astounding ideas and artifacts of preposterous scale, but if you don’t include an ironic, or at least sarcastic, commentary yourself, a smart reader will do it for you, and at that point you’ve sort of started to lose them. A strand of undercutting humor is like a release valve letting the excess hot air out of the whole potentially absurd bubble of speculation that is SF.