In a short piece for The Guardian, David Mitchell explains how Slade House grew from a Twitter experiment — the short story “The Right Sort” —  into a ghost novel in its own right:

“Despite naming my first published novel Ghostwritten, I’d never considered writing a full-length ‘ghost novel’ until handing in the manuscript of The Bone Clocks in 2014. Some juicy scenes remained from an earlier version, and I had the idea of turning this ‘spare rib’ material into a ghost story for Twitter called The Right Sort. This I posted in clusters of tweets, timed to coincide with British commuter hours, over several weeks prior to publication of The Bone Clocks.

I like to think The Right Sort was well received: for sure, it was a lot of fun to do, but the narrative raised more questions than it answered, especially about the mysterious house and its owners. To explore these questions and concoct answers would require a short novel. My publishing cycle had settled to a comfy once every three or four years, but Slade House felt at least two-thirds pre-formed in my head, and the novelty of writing a book of less than 500 pages was tempting. I let it jump the queue.”

As he wrote the novel, he absorbed himself in the “taxonomical thicket” of horror and ghost story sub-genres, which provided the basis for the structure of the book:

“My aim was to turn the vice of repetition into the virtue of outfoxing the reader by using assumptions acquired previously. Every nine years, between 1979 and 2015, a ‘visitor’ is steered at the end of October down Slade Alley to a small black iron door. Waiting for each visitor behind the door is a bespoke trap that they navigate and interpret in ways dictated by who they are.

Waiting for the reader is an alternate sub-genre of the ghost story. If you have time and inclination to drop into Slade House, I trust you’ll enjoy your visit. In an ancient, primal kind of way.”

Nathan Bishop, with his Valium habit and his fretting over whether bad pills are responsible for what he’s seeing, probably falls into the “ghost-as-symptom-of-insanity sub-genre,” as Mitchell describes it.

What about Detective Inspector Gordon Edmonds? Is he part of what Mitchell calls “the cloaked ghost story, where the ghost passes unnoticed until the big reveal”? I have to admit, up to a certain point I wasn’t sure whether Chloe Chetwyn actually was Norah Grayer, before the idea of the orison-as-“bespoke trap” was firmly established, at least in my mind. Were other readers wondering the same thing until late in the chapter, when it became clear that Norah-as-Chloe was toying with Edmonds? (Side note: Did Edmonds ever really leave Slade House during the week or weeks that passed during his courtship with Chloe? Or did the Grayers expand the orison to fool Edmonds into thinking he’d left? Did any of the things he did on the outside actually happen, or were they just part of the larger simulacrum?)

The meta-story about ghost hunters is pretty easy to pin down — that’s poor Sally Timms and her friends in her college paranormal club, who took a skeptical approach to Slade House, complete with xeroxed sheets detailing earlier Slade House victims and the nine-year open day cycle. But that chapter quickly goes from ghosthunting tale to brutal emotional manipulation, dangling things Sally’s always wanted right in front of her face only to snatch them away at the last instant. ( “A sprinkle of last-minute despair gives a soul an agreeably earthy aftertaste,” Jonah Grayer explains afterward.)

Her sister Freya’s chapter could be a combination of the meta ghost story and the “nervous breakdown” subgenre — Freya agrees to sit down with Famous Fred Pink at the Fox and the Hound because she’s desperate for any piece of information that can help her find out what happened to Sally. But it doesn’t take long before she’s decided Fred is a “nutter” and she sits there, sipping her banjax and nodding condescendingly as she listens to the old man. When she checks her phone and sees a series of increasingly worried texts from her significant other, she still doesn’t get it — not until she tries to leave the bar and realizes she can’t does she finally put two and two together, and realizes she’s already inside Slade House.

One of the interesting things about this is that we’ve already seen Mitchell pull off the genre-hopping trick, but with Slade House he’s shown us an entirely different way of pulling it off.