Sulari Gentill in Crime Reads:
It is the nature of progress that what is now cutting-edge will, with the passing of time, become traditional. And it is the nature of human beings to remake and refine what has worked in the past, and call it new.
And so the term “traditional mystery” is from the outset somewhat difficult to define absolutely. It has an almost organic structure, with successive authors and generations adding their own extensions and renovations to the house built by the likes of Poe, Christie, James, Sayers and Conan Doyle.
That original house had a foundation built on the reassurance of the middle classes, and four recognizable walls: the amateur detective or private investigator with superior powers of deduction, violence and sex occurring largely off-stage and referenced rather than shown, an incompetent or indifferent police force and, above all, the restoration of social order.
Over the years, Hardboiled, Noir, Forensic and Suspense have moved into the street and Traditional crime has been influenced by the architecture of its neighbors. Its walls have been repainted, moved and even knocked down to improve both the view and street appeal for contemporary tenants.