Because this distinction of genres is aimed at letting you know where to put your stuff, I’m going to kind of race through science fiction.
There is a reason for that: in the last 20 years or so, since I had the inside view of publishing, science fiction has got short shrift. So if you are writing science fiction at all, you’re going to be sought out by people who read science fiction.
One exception is hard science fiction. If you’re writing hard science fiction, like writing historical anything, make sure you have all your facts in order, because they will eat you alive, without pausing to slather on mustard. Also in hard science fiction your facts must be as much as possible plausible to present day.
The only caveat I have if you’re writing hard science fiction and you get your story from the plot out, do yourself a favor and buy this book: Creating Characters: How to Build Story People by Dwight Swain.
I apologize if you’re the one in a thousand hard science fiction writer who really gets his stories from people, but the two types of mind don’t seem to work the same and I’ve found myself loving the concept of many a book while huffing at the wooden puppets instead of characters. Read the book. It will be good for you. Other than that, write more. Other than Asimov, hard sf writers seem to not be incredibly prolific.
The other thing is that hard science fiction readers don’t seem to like any other kind of science fiction and look down on them as though they were the poor stepchild. To that I say tough noogy.
I like and enjoy hard sf, but what captured me for science fiction first was the crazy, which might as well be fantasy, Clifford Simak’s “Out of Their Minds” and space opera, i.e. Robert A. Heinlein’s Have Spacesuit Will Travel.
Years ago, when I was trying to figure out this stuff (I’d written one, unsaleable novel, and was 23) I bought Orson Scott Card’s book on writing science fiction and fantasy (very recommended if you’re a raw beginner, to work some crazy fidgets out. The thing that stuck with me was “don’t call a rabbit a schmerp.”)
He was brutally honest about how publishers viewed the difference between science fiction and fantasy: trees are fantasy; machines are science fiction.
I thought he was oversimplifying and made fun of this for years. In fact, I have a started (might be finished, I haven’t looked through old diskettes) novel called Big Bright Shiny Machines which makes fun of this entire concept.
BUT I was a twerp and should have known it. He was right, as far as the establishment was concerned. I found this out when I wrote a novel (Witchfinder) which had both magic and was part of a chain of worlds, of which we were one. Because the main female character is pulled from our world, and starts out as a computer programmer I was told the book is “neither science fiction or fantasy.”
I don’t think this applies to readers, mind. I think it’s one of those traditional publishing crazinesses that took over in recent years, as they hire more recent college graduates who never read the genre. Because my world was not patterned, but fit into a subgenre of multiverse hopping, some with magic that includes Diana Wynne Jones Chrestomanci. And no one tried to say those were “neither science fiction or fantasy.”
From a reader’s point of view, to me, what distinguishes sf from fantasy is that SF at least TRIES to be logically derived. Yes, there might be things in that time that are “impossible” in ours, but depending on far away it is that doesn’t hang my disbelief by the neck till dead, because, well, think of how we live. I’ve long decided if there was a time slip, and middle ages people came to us, they’d think they were in fairyland. We are ridiculously long-lived and have very few children, like the elves, too.
Fantasy, on the other hand, needs only follow internal logic, which does NOT need to relate to the logic of our world.
If you’re straddling the line and want to be thought pure sf, if your choice is between elves and time travelers, or elves and aliens, just monitor your words. Not spells, but something else. Come up with something scientific-y sounding. Heinlein’s “sensitives” were a touch of magic in his science fiction, and if he’d called them “low grade mages” it would have put the entire thing in fantasy.
I’m told sf/f straddle is a thing, so if you want to do that, shine on you crazy diamond.
In science fiction, off the top of my head and as usual missing a ton of things that escape my uncaffeinated morning brain, I can think of the following categories:
Reality with a twist – the world is ours, the reality is our everyday one, but there’s a science fiction element, usually mysterious or at least it might not be explained till the end of the book, but it affects and changes the world and all in it. This can be mini black holes opening everywhere; we find the sun is sentient and is pissed at us; or there have always been aliens among us, living disguised, or a ton of other twists. For a while there, in the eighties, this was the favored “science fiction” of big houses. For a gonzo example of this that is probably not to the taste of current houses, try They Walked Like Men, which will make you feel very uneasy driving in mountain roads, when the car behind you has makeshift headlight arrangements, or, now that I think about it, selling a house. I was thinking of this book through our endless house search.
It can be done very well, and when it is it leaves you breathless, however like Magic Realism it is an incredibly difficult art form, and most practitioners just manage to make it blah. Okay, that’s true of most writing, but this one challenges even writers who would be fine in other subgenres.
Next up, in “distance from the real world” are science fiction thrillers. More or less like the above, but the thing that’s different is valuable and someone is trying to get it/make sure it doesn’t fall in the wrong hands/kill someone for it/destroy the world with it. Whatever.
Hard SF comes next. It’s usually — but not always — got some element of space. Even if we’re not in it, this change whatever it is, relates to space. Again, not always, but the ones that sell well seem to have this. I’ve talked a bunch about the genre above, so no more on it need be said.
Next up is Time Travel science fiction. This differs from time travel fantasy in that the mechanism is usually explained in science terms, and from time travel romance in that there are usually (but not necessarily) a lot fewer hot guys in kilts. Either the dislocated come to the present, or we go to the past. Your principal care should be that there should be a semi-plausible mechanism for time travel, even if it’s just “we discovered how to fold time” and if you’re taking your character into historic times, for the love of heaven, make sure you have those correct. My favorite — to no one’s surprise — of these is The Door Into Summer which does not take you to past times. Of those that do, the favorite is The Doomsday Book by Connie Willis. My one caveate, re: putting it on Amazon is for the love of heaven, I don’t care if you have a couple who fall in love, do not put this under time travel romance. Do not, do not, do not. You know not what you do.
Next up is Space Opera — my definition, which is apparently not universal — Earth is there (usually) and the humans are recognizably humans, but they have marvels of tech we can’t even guess at. The tech or another sfnal problem (aliens!) usually provides the conflict, and there’s usually adventure, conflict, etc. My favorite is The Moon Is A Harsh Mistress. (And by the knowledge of his time I think it was hard SF except for the sentient computer which we STILL don’t have. Yes, I cry when Mycroft “dies” What of it?)
Bleeding in from that and what many people actually think Space Opera is EXCLUSIVELY (It can be a sub branch of space opera. But these people say space opera is if you have my lord and my lady in space. They’re young. They should get off my lawn already) is what I call “vast empires in space” which can be shortened to “lords and ladies in space.”
It usually is science fiction because GOOD practitioners of the art don’t just wave their hands but take in account what different planetary conditions do to people and human society, etc. I.e. they assume some things that are fantastic to us, like say faster than light, but they use reason and extrapolation for practically everything else. I feel uneasy with the genre (which doesn’t mean I don’t promise to write it) mostly on the political speculation, because my internal clock says the idea is “off” for the vastness of space, but if you’re going to read it, you can’t go wrong with Lois McMaster Bujold. (Yes, I know not precisely that, but close enough for government work, like the Door Into Summer with time travel.) This is a sub branch of Space opera to an extent, but distinctive enough to merit mention. Since I haven’t put any up on Amazon I don’t know how you signal it, but I’m going to guess you put words like “king” or “queen” in the key words. It has its devotees and people like me who approach it uneasily because …. from the pov of space and humans it doesn’t seem right. OTOH how am I to tell others how to dream?
Bleeding in from that, and as a subgenre of both space opera and empires in space is military sf. It can also be a subgenre of hard sf or near future (few changes) sf. It involves the military. There’s a war. I haven’t read much of it other than David Weber. I don’t have anything against it, mind, just nothing has really captured me or if it has, it was forgetable enough the brain can’t call it up sans caffeine.. The grandad of the genre is Starship Troopers.
There used to be a very common subgenre, which I’d love to say was in the seventies, but I’ll be d*mned if I know, because in Portugal things were translated whenever, and sometimes decades late, which I called “space colony or planetary exploration.” I suspect the grandad of that is Tunnel in the Sky. Thing is, you drop a bunch of people either on purpose or by accident, to explore the planet, and then it’s a test of character and moral fiber. At some point the writers rebelled against the “some people are more fit for survival than others” trope, and we got characters who were all despicable and where either no one survived or the nastiest survived. What you could call Alferd Packer fiction. I stopped reading it shortly thereafter. I haven’t seen much in this in Amazon, and wonder if there’s a market for it without the nihilism and human hatred, but I have had neither the time nor the inclination to explore it.
Okay, right now, off the top of my head, this is what I have.
My big caution, and hence the title is that some indie authors, for reasons unknown to me — maybe they don’t read in the genre, maybe they think other people don’t — is that some authors insist on reinventing the wheel.
Sure, tell us your computer gained consciousness by THIS method, but don’t stand there and give us an history of how AI shouldn’t be possible, and deary me, this is what computers are. Because anyone who reads SF either knows what AI is or can infer it from context.
And for the love of BOB unless you’re actually writing middle grade YA do not have a glossary on the front defining such “difficult” terms as robot and spaceship. Because what will happen then is that when my husband stumbles on your book during a late-night reading jab, he’ll wake me to read me these definitions in a dramatic voice. And I will never forgive you. Ever. Ever. Ever. Being awakened at 3 am is NEVER funny. So don’t do that. Read a little in the field and assume your readers know what you’re talking about. (Unless you’re writing science fiction romance — romance, groan, next week — in which case you’ll find you do need to explain all that stuff, as these readers aer not preferentially SF geeks.)