We typically put fiction into one of two categories: It's either a short story, or it's a novel. But there is another variation that lands somewhere in between the two. Yes, the novella. What exactly separates a short story from a novella from a novel, you ask?

As with most art forms, the label is somewhat malleable. When it comes down to it, though, it's all about word count. Atonement author Ian McEwan, discussing his love of the form in The New Yorker in 2012, defined the novella as being between roughly 20,000 and 40,000 words. Writer's Digest says it can run up to 50,000 words. Around 30,000 is more typical.

Anything more than that 50,000 words is probably a full novel. Short stories, which are designed to be read in one sitting, are usually only a few thousand words long and written for publication in a magazine or as part of a collection. The highest word count many literary magazines will publish is around 10,000, but most stories are even shorter, under 7500 words or so.

This leaves the novella in a weird in-between space where it's too long to publish in a magazine or literary journal and too short to publish as a book. (Yes, there's another in-between category for those stories between 10,000 and 20,000 words: the "novelette.") For publishers, putting out a novella isn't a very attractive option. Novellas look pretty small once they're bound, and customers aren't always keen on spending hardcover prices for teeny-tiny volumes.

Some of the difference between the forms is just marketing, though. Novellas have been around since the Middle Ages, and some standard English class assignments are on the list. Even if you don't know it, you've surely read one, probably thinking that it was just an extra-long short story or a rather short book. Perhaps it was Joseph Conrad’s Heart of Darkness, or Charles Dickens's A Christmas Carol, or Franz Kafka's The Metamorphosis. Maybe it was Edith Wharton's Ethan Frome or H.G. Wells's The Time Machine. All can be classified as novellas.

Despite the fact that these novellas turned into classics, you probably don't see a lot of contemporary examples at your local bookstore. Even the most popular writers have trouble finding a publisher willing to take on their in-between length stories. Stephen King, or example, struggled to get them out into the world until he finally published Different Seasons, a collection of four of his novellas, in 1982. And that had nothing to do with the quality of those stories; one was later adapted for the screen as The Shawshank Redemption.

In the afterword to the book, he wrote of the trouble he faced getting the novellas published because they were "too long to be short and too short to be really long." When he pitched his editor on a book of novellas, King recalled, the editor was polite, but "his voice says some of the joy may have just gone out of his day." In the end, he got the book published, but even for a hugely popular author, it was an uphill battle. Even for the biggest names in publishing, it seems, the novella is a no-go.

But that doesn't mean you shouldn't seek them out; according to McEwan, they're the "perfect form of prose fiction." Even if they go on a little longer than 10,000 words.

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