Trilogies seem to be prevalent in fantasy, but there are a disproportionate amount of sequels in general it seems. Why is this?

The ratios described in the link, and below are (roughly) 1:8 for fantasy, 2:3 for sci-fi and 1:1 for horror (the best data I have on non-spec-fic).

2010 Novels, Sort Counts

Stand-alones Sequels and Series Totals
SF Novels 60 99 159
Fantasy Novels 46 278 324
Horror Novels 11 10 21
totals 117 387 504

Is this difference statistically significant? Is there a better data set available?

  • Yeah, that's definitely statistically significant...
    – C. Ross
    Commented Aug 8, 2012 at 19:31
  • It looks it sure, but I'm not a statistician damnit, I'm a physicist.
    – AncientSwordRage
    Commented Aug 8, 2012 at 19:37
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    If you look at Locus' list, there are lots of Fantasy entries like the first three: locusmag.com/Monitor/2010/Directory1a.html#fn Three books, published in Oct, Nov, and Dec of the same year doens't seem to me to be an author "returning to earlier works" That might be three books, but I'd count it as "one work." Similarly, I'd call the classic Foundation Trilogy to be one work, then the later novels to be sequels, but I'm not sure I'd call Foundation and Earth a sequel to Foundation's Edge... it's more of a continuation. Commented Aug 8, 2012 at 20:21
  • 1
    I think it's still an interesting question, but I might edit "sequels" in the title and question to "sequels and series." Commented Aug 8, 2012 at 20:22
  • 1
    I think that your genres for comparison might be flawed. There are fantasy novels which operate closely to the type of novels you find in sci-fi, but you don't have a romance sci-fi to compete with the romance fantasy. Romance writers crank out a book every year in their chosen universes and rarely recreate their setting. It's a serial medium and it doesn't compare to how sci-fi and non-romance fantasy is written. Commented Aug 8, 2012 at 22:35

5 Answers 5


Creation of an entire world is long and hard work, and you want to get the most return out of your investment.

Most fantasy authors spend years on building their fantasy setting, unlike SciFi, which is often set in a much closer and more recognizable setting, or even in modern times, or a loosely metaphorical setting.

In the High Fantasy genre, it's considered the norm to build a detailed world, with several continents, dozens of kingdoms, a basic magic system, history, monsters and an epic struggle. If you only write one book, you would a) not be able to transmit even a smidgen of this to your readers, and b) have an awful lot of world unexplored except in the back of your head.

So write a trilogy! Let the epic quest stretch on from sea to shining eel-infested magic-conductive used-to-be-an-ancient-empire-that-sank-beneath-it sea!

  • Yeah! Once you're already so enmeshed, it seems like such a shame to leave some of those details out.
    – rsegal
    Commented Aug 9, 2012 at 13:47
  • Alternately, write more stories in the same setting! If your "main quest" winds up drastically altering the world, write a series of vignettes from before the events and how various people cope with the changes! Once you've built yourself a compelling and detailed world you can mine it for material for /ages/... Commented Oct 28, 2014 at 12:28

I'd posit that there may be too many disparate reasons, some may be:

  • Less commercial demand for SciFi? Meaning, there are fewer books that bring in enough revenue to warrant a sequel? (or to reverse, Fantasy books bring in more money overall meaning the likelihood of a sequel is higher). We need lots more raw data to test this hypothesis.

  • More commercial demand for sequels in fantasy? Could be both because SciFi readers are more receptive (or more desiring) of new worlds than fantasy ones; or some more complicated factors.

  • Misclassification. Do Alt-Hist novels get classified as SciFi or Fantasy? Only Eric Flint's stable of Assiti Shards/1632 sequels will snowball whatever category they are in; and many if not most Alt-Hist works have many sequels.

  • Perhaps it's easier to tell a self-contained SciFi story with no need to expand (this is a creative drive side, as opposed to commercial demand as last bullets). As an example, Eric Flint explicitly answered the fans that he has no plans to write a sequel to his excellent and widely liked debut SciFi book, Mother of Demons, because he sees no way to write a book's worth of interesting story as a creator.

    ... I doubt if I’ll ever write a sequel to MOTHER OF DEMONS. I once asked Jim Baen his opinion on the matter and his advice was to leave the story as it stands. I think he was right. Despite the fact that I usually work in series I have always tried to avoid “series-itis,” by which I mean writing sequels simply for the sake of writing sequels. That story arc was finished and simply continuing further adventures of the heroes would serve no real dramatic purpose. (Eric Flint, July 6, 2012 at 12:37 PM)

  • It seems easier to come up with a non-horrible new SciFi universe/setting than with a fantasy one. There are only so many permutations of fantasy races, myths and magic you can have; unlike aliens, science facts and especially technologies.

    Yes, creating a unique GREAT world, à la Arda or Dune, is equally hard. But creating a "Just good enough to get published and read" may be harder for fantasy setting, since there are less variables you can mutate.

  • 1
    +1, I agree with most of what you said. But I think science fiction writers are often less interested in re-visiting places they create. They will experiment with an idea, fill it out create the universe, tell their story and BAM, they are done with it. No need to go further. The idea is finished. When they do write a sequel, often it is sometimes MANY years later. Commented Aug 8, 2012 at 22:10

I don't know where you are getting the data, if it's major publishers, minor ones, or a selection of both. Regardless of where it's from and assuming it's statistically sound, in your table, the number of fantasy sequels and series is significant. As to why this is the case, you will need to research the reasons why those sequels and series have been written.

I will postulate that there is much data that should can be included, though finding it would be a tedious process. For things that are subjective by the author, you can assign a numerical value to the entries. Examples of things to consider as a new column are:

  1. Why did the author choose to write a sequel?
  2. Was the original work too long and then was split up into various volumes by the author/publisher?
  3. Is the series written by multiple authors (The Star Wars Rougue Squadron series was guilty of this)?
  4. Was this an effect a critically acclaimed book and the author/publisher wanted to capitalize on the audience?
  5. etc

If you are able to answer these questions with data, then you would be closer to answering your question. Without knowing these subjective reasons and having data to back it up, the best that any of us can answer is by giving you an opinion.

source: I am a business analyst and a statistician


One factor might be this:

Sci-Fi, as involving as the worlds can be, are often much closer to real life than Fantasy. So it might take Tolkien the same effort, for example, to craft Middle Earth, as half a dozen of Asimov's short, speculative stories.

They're both stellar (ha, ha), but one has a product that's easier to churn out.


When I first looked at the list of Fantasy Series/Sequels in the Locus list, I was thinking of making a cynical comment along the lines of, "authors are writing tons of fantasy series in hopes of cashing in on the popularity of Harry Potter/Twilight/etc."

I was at Chapters tonight with my 8-year-old, and from looking at the 8-12-year-old and teenager sections, my cynical thought is apparently accurate: both sections were loaded with fantasy series: magic, vampires, gods, other supernatural beings... I don't see Warriors on the Locus list, but those might be considered fantasy and they took up two full shelves...

Looking at all these series on the shelves, it really seems like authors and publishers are trying hard to come up with something as popular as Harry Potter and as long-running as The Hardy Boys.

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