Till Death Do Us Part, first published in 1944, is a detective story by John Dickson Carr

John Dickson Carr

John Dickson Carr was an American author of detective stories, who also published under the pen names Carter Dickson, Carr Dickson and Roger Fairbairn....

 featuring his series detective Gideon Fell

Gideon Fell

Doctor Gideon Fell is a fictional character created by John Dickson Carr. He is the protagonist of 23 novels from 1933 through 1967 as well as a few short stories. Carr was an American who lived most of his adult life in England; Dr. Fell is an Englishman who lives in the London suburbs.Dr...

. This novel

Novel

A novel is a book of long narrative in literary prose. The genre has historical roots both in the fields of the medieval and early modern romance and in the tradition of the novella. The latter supplied the present generic term in the late 18th century....

 is a mystery of the type known as a locked room mystery

Locked room mystery

The locked room mystery is a sub-genre of detective fiction in which a crime—almost always murder—is committed under apparently impossible circumstances. The crime in question typically involves a crime scene that no intruder could have entered or left, e.g., a locked room...

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Plot summary

Dick Markham is engaged to Lesley, but he doesn't really know much about her. When they attend a cricket match in the little English village of Six Ashes, they stop at the associated fete and Lesley insists on seeing the fortune teller. She is apparently unaware that the fortune teller is being played by Sir Harvey Gilman, the Home Office pathologist and expert on crime. After her visit, Dick visits Sir Harvey, who is apparently about to tell him something unpleasant about his fiancee when he is shot—accidentally, by all reports, and certainly non-fatally—by Lesley. Later that night, Sir Harvey tells Dick that Lesley is really a murderess who has poisoned three husbands using a mysterious method of death that seemingly must be suicide, whereby the victim injects himself with hydrocyanic acid. Later that night, Sir Harvey dies in a locked and sealed room, seemingly after having injected himself with hydrocyanic acid. Gideon Fell is called in to assist the police investigation. It is soon discovered that "Sir Harvey" is actually a confidence man named Sam De Villa, and his revelations about Lesley are untrue, but this doesn't answer other important questions. What is the significance of a box of drawing pins found scattered beside the corpse? Who fired a rifle into the murder room in the early hours of the next morning? It takes another murder before Dr. Fell reveals the identity of the murderer and the method by which the room was locked.