When it first came out many fans were surprised and/or dissatisfied because the book did not live up to their expectations of a horror novel. It is written in spoken English - even in dialect - and is told by the title character. There are also no chapters in the book, not even blank lines.
Dolores Claiborne is in a police interrogation and wants to make clear to the police that she did not kill her employer, an elderly lady that she has been taking care of for many years. She starts off by confessing the murder of her husband, many years ago. The novel develops into the story of her life and all the problems she has seen.
There are very few supernatural elements in the novel. What little there is could have been left out without any major change in the plot. The reason they are there is to create a connection to King's previous novel, Gerald's Game. Some readers think that the book would have been better without this connection: It is not very important, and it is also never explained so people that have not read Gerald's Game are left in the dark. Later editions of the novel have a foreword that explains the connection.
Dolores Claiborne has been filmed as Dolores Claiborne with Kathy Bates in the lead role. The film has dropped the connection to Gerald's Game.