Context is relevant in the novel because the Murder Room referenced in the title is a museum exhibit about actual, historical murder cases that connect in some way with the new murders that are committed in the fictional work. The varied backgrounds of the characters are also relevant to different aspects of the plot because they could provide possible motives for those murders. More generally, the museum’s focus on the interwar period of British history offers a rationale for some characters’ association with the museum.

The Murder Room is one exhibit in the private Dupayne Museum. Adam Dalgliesh’s introduction to the museum and the room precedes his involvement in the murder investigation. His friend Conrad’s interest in the ways that homicides articulate with the era when they were committed establishes the importance of context as one of the novel’s themes.

The changing class relations in England after the First World War is played out in the relationships among various characters, including the three Dupayne siblings who represent the antiquated upper class. The lack of interest of Neville Dupayne in keeping the museum open is initially established as a likely motive for his becoming the first victim. However, author P. D. James generates suspense by making the reader wonder if this motive is valid or is an unfounded assumption.