I will fill in the pulp fiction (emphasis on horror) category.
This is a book that scared the ---- out of me when I first read it.
Jay Anson,
The Amityville Horror

I think most people would not believe that the events in the book happened, and that's fine. But reading it as a 11 or 12 year old I was terrified. A little context:
At that time I my family was living in England, out in the Buckinghamshire countryside. The village we lived in was called Little Marlow, it had fewer than 15 houses I think. We lived almost at the end of this tiny road. At the very end was a small ancient church and graveyard. So our massive back garden bordered on the graveyard on one side. You could look through the hedges and see old headstones clearly. This old lady used to chase me out of the graveyard. I just wanted to read the stones and dates.
Also in our backyard was a pool...coffin shaped.
My parent's went in to London to see a show with friends and would not return till early morning. I was left in the house with my brother younger sister and the friends two children. Everyone was asleep but I couldn't sleep. Why? Well I had started reading this book.
For some stupid reason, I decided to read it in the dining room with my back to the French doors to the patio and pool. It was a big old house that seemed to make the most in appropriate noises when reading such a book. I remember horrific startles when the grandfather clock would chime suddenly.
As I got more into the book I became scared to turn around and look out the french doors; sure that that damned pig of Missy's would be staring right back at me.
At some point I started to believe it was safer to stay in the dining room than to try to get upstairs to my room.
Every time the wind would rattle the french doors behind me, I was sure something was coming in. I remember sitting there shaking.
Ah good times.
Oh the book. It's about a family moving into a haunted house and all sorts of disturbing things happen to them, a preist and some of their friends. Spawned a multitude of movies.