I powered through this, probably Jim Thompson's best known novel (along with The Grifters I guess) over a few days, and it is a disturbing read. The narrator, Lou Ford, is compelled to kill, preferably women, but really he's not too choosy. There are a couple of twists, but mostly it's a straightforward tale of the sickness inside Lou, his compulsion to kill. It's not terribly gory, but it doesn't need to be; Lou's accounts of his murders are sickeningly mundane. One in particular lodged in my brain: he punches a woman in the stomach so hard his knuckles can feel her spine, which is an awful, memorable image.
God knows what Michael Winterbottom's film will be like. Apparently it's faithful, right down to a period setting (the 1950s), so I can see why, reportedly, there were walk-outs at one screening. The Killer Inside Me isn't a novel I'll soon forget, and not in a good way. Then again, maybe that was Thompson's aim, like Michael Haneke's stern cinematic lectures (Benny's Video, Funny Games, etc.): to confront the reader (or viewer) with something so vile they question their motives in reading (or watching) it.
Of course, as with Haneke, that's likely a simplistic reading. As with Haneke's films, I think there's a lot more going on in The Killer Inside Me than mere finger-wagging, although I'm not sure what yet. One to digest, then.