Had a good scare lately?

Have you ever read a book that really scared you? I mean, actually had you afraid to answer the door or walk alone at night? I remember reading Stephen King's Salem's Lot when I was a freshman in high school. For some reason that book really freaked me out. I saw vampire eyes every time I looked out my window at night, and seriously thought about stashing a few wooden stakes under my bed. It was great, though, and I couldn't stop reading. I am sure some of you guys won't actually admit to being scared by a book, but just think about a book that kind of "freaked you out a little" then. What is the scariest book you have ever read, and why do you think it was so scary?