Justin Evans's debut, A Good and Happy Child, takes a familiar concept—the young child haunted by a demon no one else can see—and infuses it with rare psychological depth.

How did the plot for A Good and Happy Child originate?

I grew up in a town very much like the one I describe in the novel, in West Virginia, in an environment where everyone believed in ghosts and everyone had their own ghost story. I'd sit in the living room while my dad told tales of demonic possession that would make grown men's hair turn white. Some of the scary details in the book—like the shower door banging back and forth—are things that I grew up with. There's one other component. As a kid, I had a really dark, miserable year, and my parents sent me to a child psychologist, which worked out great, but I took all that unhappiness from that year and packed it into the story.

Did the finished book differ significantly from what you started with?

I revised it a lot from a structural perspective. It was interesting for me to discover that what I would have considered clichéd plot structures ended up making my content better.

How early on in the process had you settled on the ending?

The original ending that was in my outline wasn't enough for me; I rewrote the ending 15 times, over one weekend, before I got to the final version, because it was so important to me to get it right. I was e-mailing paragraphs constantly to my agent that weekend. My wife helped me as well, but, having read 12 versions of the ending, she woke up screaming in the middle of the night. It had freaked her out, which I found extremely gratifying.

Are there writers of ghost or horror stories who affected the way you treated your book's supernatural themes?

My inspirations were supernatural chillers that are what I like to call delicious reads—in particular, Dracula and The Turn of the Screw. Readers who know the Henry James story will recognize many elements of it in my book, especially in how I ended it. In earlier drafts, the book had more of a fantasy element. I tried to imply that the three adult characters who try to help George Davies [the novel's narrator] are almost like living saints, with magic powers, but it didn't work.