Had only read one Peter Straub book before (Lost Boy/Lost Girl) and his collaborations with Stephen King. While I liked the few books I've read, I never found anything to be truly terrifying. Ghost Story, however, takes the cake. Easily one of the top 5 (6) scariest, most frightening books I have ever read. Certainly was a mistake to read this before bed, or before I walked the dog at 1:00 on a pitch-black night.
A somewhat familiar story - Something evil comes to town; wants to destroy the town; a handful of residents who know what's going on have to stop it (Something Wicked This Way Comes, Needful Things) - this one is slightly different because the evil comes back to the small town for revenge against the Chowder Society of 5 local men. But the creeps weren't the usual "boo! i jump out from behind the door and scare you!" they were well crafted, situations that went against the conventional normal and made your skin crawl.
A MUST read for all horror fans.
EDIT - My top 5 (6) scariest, most frightening books:
1) Stephen Kings's "It"
2) Ray Bradbury's "Something Wicked This Way Comes"
3) Stephen King's "Salem's Lot"
4) Neil Gaiman's "Coraline" (do NOT laugh.....yes, I know it's a kid's book)
5) Peter Straub's "Ghost Story"
6) Shirley Jackson's "The Haunting of Hill House"