What Book Terrified You To The Bone?

What is the scariest work of fiction ever penned? What made your hair stand on its end? We want to know about the scariest book you ever read.

This is a fairly selfish open channel request because I need a new book! And I want a skin tingling, hair standing, knock down horrifying read for the summer. Something that has me looking over my shoulder the whole time! If I had to pick the all time most terrifying book, I would have to say.....

What Book Terrified You To The Bone?

The Shining by Stephen King

This book was particularly hard to get through in a chill level. Second would have to be the books pictured above (in that order!). But now it's summer and while everyone is reading about love on the sands of their blissful summer vacay, I want to be reading about pissed off spirits, murders and mysteries. Please recommend the scariest book you've ever read.