A steadfast spooky book is hard to find. The best type of horror book is the kind that really scares you. The following books do an excellent job with that, and it is not always because of a ghost:
Haunted (by Chuck Palahniuk): Some people in a vast ancient theater are led into believing that their dilemmas will turn into the greatest piece of creative work in the world, and the more downhearted their circumstances become, the more hungrily they resort to trickery to achieve it.
The Haunting of Hill House (by Shirley Jackson): Four people at a very old house cope with terrorizing episodes, whilst the house itself seems to have a life and will of its own.
The Exorcist (by William Peter Blatty): After creepy episodes such as a freezing bite, the scattering of furniture and a noisy environment in the attic, it appears that Regan might be possessed by a satanic spirit.