A couple of weeks ago, I wrote about a type of story (strangers in buildings) that I’ve developed a liking for. Then a commenter asked when something could be considered a fully fledged genre of its own and I’ve been thinking about it ever since. I haven’t come up with anything definitive, other than to say a genre is a bit like the canon. We know roughly what belongs where, but the boundaries move depending on who you talk to. The problem is that there are so many things that go into defining a genre, from plot to pacing to style to characterization. There are so many variables that it’s practically an invitation to argue about what separates one genre from another.

When I was a young reader, I knew about the traditional genres: mystery, fantasy, science fiction, historical fiction, literary fiction, etc. When I got older, I learned about more genres: psychological thrillers, then urban fantasy, all the different kinds of punk genres, and my beloved metafiction. The more I look, the more genres and sub-genres I find.
What I have seen in my years of reading is that someone will come up with something new. They’ll blend elements of different genres, like tossing vampires into a mystery to create urban fantasy. Or an author will introduce a variation that takes an established genre in another direction, like writing about detectives who bake or knit; suddenly, we have cosy mysteries. The new thing has to reach a certain kind of critical mass, enough popularity that readers and publishers have to name the thing. And, once it has a name, voila, a new genre! It’s all based on popular acclaim, as far as I can tell.

Makes sense to me!
Man, I remember when I’d used to walk through Borders or Barnes and Nobles and be surprised about the labels for genres I’d never heard of (“supernatural tween romance” or something to that effect stands out). With most of those stores going out, however, I guess aisle signs will no longer be the arbiter of knew literature types!