The Haunting of Hill House

Shirley Jackson's slim novel The Haunting of Hill House (1959) follows the misadventures of a group of people recruited by Dr. John Montague, a would-be specialist in the "analysis of supernatural manifestations," as they attempt to document the goings-on at Hill House. Hill House ("not sane"), erected in the late nineteenth century, was commissioned by one Hugh Crain—whose first wife died before she even managed to enter the house. His second wife also died. And the third. If this run of suspiciously bad luck wasn't enough, the house has since seen a run of mysterious events, suicides, and strange accidents, all of which have left it with a very unfortunate reputation indeed.

The main characters

Dr. John Montague: The rather fluttery Dr. Montague does his best to study Hill House "scientifically," although he proves completely incapable of understanding what's going on. As we later discover, he's also dominated by his wife, an enthusiast for all things paranormal.
Eleanor Vance: Most of the novel is told from Eleanor's perspective. She's thirty-two, unmarried, and under the thumb of her annoying family. For Eleanor, the trip to Hill House represents a last-gasp attempt to free herself from her old life.
Theodora: An artistic type who lives with a lover of unidentified gender, and flirts with both Eleanor and Luke Sanderson.
Luke Sanderson: Identified point-blank as a "liar" and a "thief," Luke is on the scene because Hill House belongs to his family; he's also the intended heir.

And, last but not least...

Hill House: The house is a character in its own right, exuding evil from the very slope of its roof.

In the tradition of Jackson's classic short story "The Lottery," most of the novel's horror derives from Mind Screw instead of graphic terrors. The Haunting of Hill House was adapted to the screen in two films named The Haunting (1963 and 1999), of which the former is considered a classic in its own right. The latter... not so much.

Not to be confused with fellow horror movie House on Haunted Hill.

Tropes used

Abusive Parents: The former children of Hill House.
A House Divided: Thanks to Hill House's little games. The tactic works most effectively on Eleanor.
Ambiguously Gay: Theodora.
Being Watched: Everyone, by the house. Later on, Eleanor begins spying on the others.
Big Fancy House: An extremely creepy variant.
Bizarrchitecture: Everything's slightly off, from the floors to the walls. As a result, doors never stay open...
Blank Slate: Eleanor whose identity revolves around more powerful personalities around her.
Creepy Housekeeper: Mrs. Dudley.
Crusty Caretaker: Mr. Dudley.
Demonic Possession: The House is able to influence, possess and even devour people.
Driven to Suicide: In the past, the "companion" who inherited the house instead of Crain's younger daughter. In the present, Eleanor.
Dying Town: The crumbling Hillsdale.
Dysfunctional Family: Every single family in the novel. Hugh Crain's family, needless to say, takes first prize.
Extreme Doormat: Eleanor, first to her mother her entire life, then to her sister, and finally to the house.
Genius Loci: Hill House itself.
Ghostly Chill: There's a suspicious chill right before you enter the nursery.
Haunted Heroine.
Haunted House: One of the classic examples.
Hearing Voices
Henpecked Husband: Dr. Montague.
Holier Than Thou: Hugh Crain, whose version of Christianity seems to have been somewhat unusual. That book he leaves for his daughters...
Mind Screw: The house invites Eleanor to "come home," tempting her with one of the most important things she lacks.
Nothing Is Scarier: A point most notably lost in the 1999 adaptation.
Romantic Runner-Up: Eleanor for both Theodora and Luke.
Shrinking Violet: Eleanor
Our Founder: The apparently horrific statue of Hugh Crain and his daughters.
Unreliable Narrator: Or, rather, unreliable third-person POV. As the story progresses, Eleanor's perspective becomes noticeably warped.
Uptight Loves Wild: Eleanor/Theodora
Where It All Began: The final paragraph repeats the opening.
Wild Mass Guessing: What, exactly, is haunting Hill House? Jackson won't say.