Father Knox’s Decalogue
The Ten Rules of (Golden Age) Detective Fiction
Monsignor Ronald A. Knox (1888-1957) was a British clergyman, editor, a literary critic, a humourist and a detective story writer himself who nicely laid out, with a gentle wit, the “ten rules” that guided detective fiction in its so-called Golden Age. They appeared in the preface to Best Detective Stories of 1928-29, which Knox edited.
- The criminal must be someone mentioned in the early part of the story, but must not be anyone whose thoughts the reader has been allowed to follow.
- All supernatural or preternatural agencies are ruled out as a matter of course.
- Not more than one secret room or passage is allowable.
- No hitherto undiscovered poisons may be used, nor any appliance which will need a long scientific explanation at the end.
- No Chinaman must figure in the story.
- No accident must ever help the detective, nor must he ever have an unaccountable intuition which proves to be right.
- The detective must not himself commit the crime.
- The detective must not light on any clues which are not instantly produced for the inspection of the reader.
- The stupid friend of the detective, the Watson, must not conceal any thoughts which pass through his mind; his intelligence must be slightly, but very slightly, below that of the average reader.
- Twin brothers, and doubles generally, must not appear unless we have been duly prepared for them.
In the eighties, Josef Svoresky wrote a mystery entitled Sins for Father Knox, which set out to deliberately break all these rules. Though this isn’t a masterpiece of crime writing there are many that broke the rules which are.