What Is Speculative Fiction? A Genre Guide for Writers
Here's your complete guide to the speculative fiction genre, its subgenres, and why it matters for your book.
Have you heard the term speculative fiction and thought...
Okay, but what does that actually mean?
You're not alone. It's one of those terms that gets thrown around a lot in writing and publishing spaces, and depending on who you ask, you'll get a slightly different answer every time.
I'm Leslie. As a developmental editor and book coach for fiction, genre is genuinely one of my favorite things to dig into with writers. Figuring out where your book fits in the landscape of everything that's out there? It matters more than most people realize, and we're going to get into exactly why by the end of this post.
But first: what even is speculative fiction?
By the end of this post, you'll understand where the term came from, how its definition has evolved, what subgenres fall under it, and, most importantly, why any of this actually matters for the book you're writing.
Let's jump in!
A quick note on the rise of this term
Before we get into the definition, here's something kind of interesting: I was curious about how this term has grown in popularity over time, so I pulled it up on Google Trends. The search volume started pretty low, held steady from roughly 2010 to 2021, and then, in the last few years, spiked significantly.
So this isn't just a niche publishing term anymore. Writers are actively looking for it, which means understanding it is more relevant than ever.
Where did “speculative fiction” come from?
The term was originally coined by Robert Heinlein in his essay, "On the Writing of Speculative Fiction," which I'll link in the resources below if you want to give it a read.
When Heinlein first used the term, he meant it essentially as an alternative label for science fiction, specifically, his style of science fiction, which was more focused on people than on gadgets or technology.
By 1949, he got more specific. In a letter that later appeared in Grumbles from the Grave, he wrote:
"Speculative fiction is not fantasy fiction, as it rules out the use of anything as material which violates established scientific fact, laws of nature, call it what you will, i.e., it must [be] possible to the universe as we know it."
So under Heinlein's original definition, speculative fiction was actually pretty narrow. Dragons? Fantasy. Time travel? Fantasy. If it couldn't theoretically exist within the laws of the universe as we know them, it didn't qualify.
Margaret Atwood, author of The Handmaid's Tale, held a similar view, defining speculative fiction as literature dealing with scenarios possible within the realm of known science, rooted in present-day or near-future settings.
How the definition has evolved
But today…that narrower definition feels pretty dated.
The way most people, and most of the publishing world, use the term today is much broader. The Speculative Literature Foundation puts it this way:
"Speculative literature is a catch-all term meant to inclusively span the breadth of fantastic literature, encompassing literature ranging from hard science fiction to epic fantasy to ghost stories to horror to folk and fairy tales to slipstream to magical realism to modern myth-making."
That's a very different scope than Heinlein's original definition, and it's the one that's actually most useful for writers today.
The older view was about speculating the possible. The modern, broader view includes speculating the impossible, too. It's about any story that asks what if in a way that pushes beyond everyday reality, whether that's grounded in science or entirely fantastical.
The main subgenres of speculative fiction
So what actually falls under this umbrella? Here's a breakdown of the major categories with examples you'll probably recognize.
Fantasy
Fantasy uses magical and supernatural elements as a core part of the narrative. Some subgenres include:
High fantasy: entirely fictional worlds with their own rules (The Lord of the Rings by Tolkien)
Epic fantasy: large-scale stories with grand settings and complex plots (A Song of Ice and Fire by George R.R. Martin)
Dark fantasy: fantasy blended with horror (The Black Company by Glen Cook)
Urban fantasy: magic in a modern, real-world setting (The Dresden Files by Jim Butcher)
Mythic fantasy: rooted in mythology and folklore (American Gods by Neil Gaiman)
Science fiction
Science fiction explores the potential of scientific advancements to challenge our understanding of the world and universe. Some subgenres include:
Hard sci-fi: scientifically rigorous and technically detailed (The Martian by Andy Weir)
Soft sci-fi: more focused on social sciences and speculative societies (Dune by Frank Herbert)
Cyberpunk: dystopian futures with advanced technology (Neuromancer by William Gibson)
Post-apocalyptic: life after catastrophe (The Road by Cormac McCarthy)
Dystopian: nightmarish societies and systems of control (1984 by George Orwell)
Horror
Horror aims to evoke fear, dread, and terror, often exploring the supernatural, the grotesque, and the darker aspects of human experience. Some subgenres include:
Psychological horror: focused on mental and emotional states (The Haunting of Hill House by Shirley Jackson)
Gothic horror: dark, atmospheric, often romantic (Dracula by Bram Stoker)
Cosmic horror: the insignificance of humans in an indifferent universe (H.P. Lovecraft)
Supernatural horror: ghosts, demons, entities (The Exorcist by William Peter Blatty)
Magical realism
In magical realism, the world is grounded in reality, but fantastical elements are treated as completely normal. The most well-known example is One Hundred Years of Solitude by Gabriel García Márquez. This genre tends to focus less on plot-driven fantasy and more on the emotional and philosophical weight of the magical elements woven into everyday life.
Fairy tales and folklore
This category features fantastical and magical elements, often characterized by their simplicity and moral underpinnings. Think Grimm's Fairy Tales on the traditional end, or The Bloody Chamber by Angela Carter for a more modern, literary take.
Okay, but why does any of this actually matter?
Here's where we get practical. Knowing your genre matters for your career as a writer. There are two main ways it shows up:
1. How you describe yourself as a writer
Speculative fiction is actually a really useful umbrella term for identifying yourself, especially if you write across multiple genres. Instead of listing every specific type of story you write, you can say, "I write speculative fiction," and people in the publishing world will immediately understand the general territory. That's how I use it when I describe my own editing work. Sometimes I say I edit speculative fiction, because it's faster than listing fantasy, sci-fi, horror, and everything in between. And if someone wants more detail, I can always go deeper from there.
2. How you market your book
Here's the flip side: when it comes to actually marketing your book, especially if you're pursuing traditional publishing, speculative fiction alone is not specific enough. Agents, editors, and readers need to know exactly where your book belongs on the shelf. What type of fantasy? What flavor of sci-fi? What horror subgenre? The more specific you can get, the easier it is to:
Find the right agent who represents your specific genre
Pull accurate comp titles that signal your book's audience
Get your book into the hands of readers who are already looking for exactly what you wrote
Getting the genre right isn't just a marketing checkbox. It's how your book finds its people.
Want to know if your story has real potential?
Here’s a fun, thoughtful worksheet for speculative fiction writers who want to know whether their story idea has real potential before they spend months drafting. You’ll evaluate your idea, spot red flags early, and get clearer on what’s working, what needs development, and whether this is the story you want to keep building.
Happy Writing!
-Leslie
P.S. You can read Robert Heinlein’s On the Writing of Speculative Fiction here.
