I am not a horror reader. If I watch one spooky trailer, I am in for at least one sleepless night with all the lights on. A few years ago, in the interest of leaving no genre unread, I decided to implement the Wimpy Librarian Challenge. Every October I have to read something far outside my personal scary zone. This year my read was "The Exorcist" by William Blatty (especially since I had *gasp* seen the movie but never read the book).
The movie follows the book almost exactly (which is unsurprising, considering William Blatty wrote the screenplay for the film). The young daughter of an actress is possessed by demonic forces. Two Catholic priests, one filled with doubt amidst personal tragedy and the other frail after a long life battling evil, are the only things standing between the girl and ultimate darkness. One thing that this story does exceptionally well is the atmosphere. You feel the dread building from the first eerie bumping noises to the ugly violence of the complete possession. Chapter by chapter, this book sucks you in. It is an absolute must read for those who enjoy a really frightening story. If you were sufficiently creeped out by the movie and want the immersive experience of the book, check out this book for Halloween 2013.
However, a word of warning: you might want to leave the lights on.