I'm not even going to reduce myself to plumbing the depths of the question of whether or not this is a "true" story...I'm reviewing the film, and much like "The Texas Chainsaw Massacre" (which we know to be fiction) or "The Fourth Kind" (of which the jury's still out in my case), the "truth" of the matter is irrelevant.
I actually read the novel before I saw this movie, but in those younger days I didn't really absorb the undercurrents of the story on the written page.
As is the way of things, time passes, the film is released...sadly, I missed the theatrical run, and first caught it on network TV, heavily advertised and edited, prior to one Halloween way back then...
I'll admit it; scared the stew out of me, Ti-Di-Bowl and K-Tel Record collection commercials notwithstanding. My own home became a nightmare place of strange sounds and looming shadows, even moreso than it already was to a kid of my imagination (with parents that let me read that kind of stuff).
Time passed...but I always fondly remembered that tension, that suspense, that WRONGness that the film inspired in me.
A lot of people don't like this movie, and I wonder if it's because of it's purport to be true; if that's the case, close-mindedness is keeping a lot of folks from enjoying what is a startlingly effective film. You have excellent actors in Brolin, Kidder, and Steiger, as well as a remarkable supporting cast. The dread is built slowly but deliberately throughout the first half of the movie, the pacing quickening as you near the climax, when literally all hell breaks loose. We witness James Brolin, as George Lutz, completely evolve into something he's not, but at the same time, we can relate to him as his world slowly comes unraveled around him (in his book "Danse Macabre", Stephen King alludes to the social/economic horrors that this film presents, and in the context of a family on edge, I agree with this wholeheartedly). His home spews black goo out of the plumbing, it's cold all the time, he can't sleep, and his job is swirling in the bowl. Add to this the fact that his wife and step-kids seem to be falling apart, and you can almost understand why he's taken to not shaving or bathing...or talking.
THIS is where the film shines; it's ability to make you relate to the characters...sure, their plight has a supernatural cause, but we've all had to deal with one thing after another just going haywire all at once...heck, it would be easier sometimes if we DID have an evil entity to blame it all on.
That said, the supernatural elements of the film, in my opinion, are scary as hell. For those of you rare readers who may not have seen it, I won't spoil the fun; let's just say you'll look at windows and basements in an ENTIRELY new light (or perhaps, DARK, heh heh).
Everyone is entitled to their opinion, and many of those that I've heard pose excellent arguments for their dislike of the film, but as a horror fan, I have to say that I still rank it as one of the best haunted house stories ever done, and it ranks high on my watch-list.
And kiddies, if a disembodied voice tells you to "get out", by all means, LISTEN!