What follows will most likely be obvious to most Lovecraftian writers, editors, and publishers, and to many readers and fans as well. But I feel it needs saying, anyway, because not everyone understands it.
Recently, I posted a list of Lovecraftian films currently on Netflix that I recommend. Most loved the list, but a few Lovecraft fans commented that they were tired of movies being labeled as Lovecraftian when they weren’t. The gist was that if the story isn’t set in the 1920s, and/or doesn’t feature Innsmouth, the Necronomicon, or the like, they felt it wasn’t Lovecraftian.
My response was that they are Lovecraftian, but not necessarily Mythos. As a Lovecraftian editor, the way that I personally define these terms are as follows:
A Mythos story is one that features places, people, and creatures that appeared in Lovecraft’s stories. When you read a Mythos story (aka pastiche) you’re reading a story that’s set, at least to some degree, in Lovecraft’s universe.
A Lovecraftian story is one that features the themes of Lovecraft: Cosmic horror, hopelessness. The madness that comes when you realize what’s behind the curtain. Isolated and old locations. Unanswered questions about reality. Etcetera. It doesn’t matter when the story is set or who is in it — what matters is that one or more of Lovecraft’s themes are present.
There are good and bad Mythos tales, and there are good and bad Lovecraftian tales. The Same Deep Waters as You by Brian Hodge in the upcoming anthology Lovecraft’s Monsters is an example of a Mythos (or pastiche) story that is a very good read. An example of an incredible Lovecraftian story, on the other hand, is The Crevasse by Dale Bailey and Nathan Ballingrud.
(Edit: Some people might consider The Crevasse to be “Mythos” because of its Antarctic setting. I don’t, personally — and you’ll note this is a personal definition of terms, as I wrote above — but some do, and I can see why they’d feel that way. So perhaps a better example of “Lovecraftian” is in order. Sticks, by Karl Edward Wagner? Cold Print, by Ramsey Campbell? And so on.)
I hope this helps.
By the way, if you’re looking for a list of great Lovecraftian books and Mythos books, check out my recommended books list. And if you’re looking for a great Lovecraftian or Mythos movie to watch, go here.
(UPDATE: I can’t always respond to comments, but I read them. There are some good comments on this post at the Lovecraft eZine Facebook page. I had previously written that all Mythos is Lovecraftian, but someone pointed out the Brian Lumley’s work is not Lovecraftian, and I think that’s a good point.)