Hell House by Richard Matheson

For over twenty years, Belasco House has stood empty. Its shadowed walls have witnessed scenes of almost unimaginable horror and depravity. Two previous expeditions to investigate its secrets met with disaster, the participants destroyed by murder, suicide or insanity. Now a new investigation brings four strangers to the forbidding mansion who are determined to probe Belasco House for the ultimate secrets of life and death. Each has his or her own reason for daring the unknown torments and temptations of the mansion, but can any soul survive what lurks within the most haunted house on Earth? "Hell House is the scariest haunted house novel ever written. It looms over the rest the way the mountains loom over the foothills." -- Stephen King