The Haunting of Hill House is a ghost story first published in 1959, but in our day we'd probably label it a psychological thriller. Some strange things are happening at Hill House and Dr. Montague is determined to uncover the source. He brings together a couple of people known to have had previous paranormal experiences to spend the summer in the house and find the ghost. However, one of his guests, Eleanor is already pretty unstable and her time in the house wreaks havoc on her mind.
There's not much in this book that is overtly frightening, rather it is the subtle phenomenon and slow deterioration of Eleanor's mental facilities that cause anxiety. It's like the puzzled reaction of my kids after they first watched Psycho and wondered, "what's the big deal?" And Hill House is a classic in the same way, which is why many authors have clearly been inspired by it. If you've read other haunted house stories and liked them you will enjoy reading this predecessor.