Coraline by Neil Gaiman

Coraline is a horror/fantasy novella by British author Neil Gaiman, published in 2002. The book is about a very "different" girl named Coraline Jones. Coraline and her parents move into an old Queen Anne style house that has been subdivided into four flats. The other tenants include Miss Spink and Miss Forcible, two elderly women retired from the stage, and Mr. Bobo, who is training a mouse circus. The flat beside Coraline's remains empty.
During a rainy day she discovers a locked door in the drawing room, which has been bricked up. As Coraline goes to visit her neighbors, Mr. Bobo relates to her a message from the mice: Don't go through the door. At tea with Miss Spink and Miss Forcible, Miss Spink spies danger in Coraline’s future after reading her tea leaves, and gives her a stone with a hole in it for protection. Despite these warnings, Coraline decides to unlock the door when she is home by herself and finds the brick wall behind the door gone. In its place is a long passageway, which leads to a flat identical to her own, inhabited by her Other Mother and Other Father, who are replicas of her real parents. They have button eyes and exaggerated features. In this “Other World”, Coraline finds everything to be better than her reality: her Other Parents are attentive, her toy box is filled with animate toys that can move and fly, and the Other Miss Spink and Miss Forcible forever perform a cabaret show in their flat. Coraline even finds the feral Black Cat that wandered around the house in the real world can talk, however she learns he is not of the Other World... (Summary by Wikipedia)