The Children (1958)
The story begins with the brutal murder of Georgie Denbrough by a creature disguised as a clown named Pennywise while Georgie sails a paper boat in a storm drain.
Georgie's older brother, Bill Denbrough (who stutters and becomes the leader), gathers a group of seven outcast children who call themselves The Losers' Club.
The other members are Ben Hanscom (the sensitive and overweight new kid), Beverly Marsh (the poor girl who is abused by her father), Richie Tozier (the motormouth), Eddie Kaspbrak (the hypochondriac), Stan Uris (the skeptic), and Mike Hanlon (the last to join, who knows Derry's dark history).
Each child begins to experience horrifying, personal encounters with Pennywise, who manifests as the thing they fear most (e.g., a werewolf, a mummy, a leper, or a giant spider).
The Losers realize the creature feeds on the town's children every 27 years and that It is tied to the town itself. They make a blood pact to return and kill It if it ever comes back. They track It to the town's sewers and manage to wound It in a terrifying ritualistic battle, forcing it into hibernation.The Haunting of Hill House by Shirley Jackson (1959): A masterful psychological haunted house story.
The Exorcist by William Peter Blatty (1971): A horrifying and intense tale of demonic possession.
The Shining by Stephen King (1977): A classic about isolation, psychological terror, and a haunted hotel.
Rosemary's Baby by Ira Levin (1967): A paranoia-fueled story about a young woman and a sinister conspiracy.