The Knox Decalogue for Detective Fiction

 

by Pa Rock

Reader

Recently while reading an article in Ellery Queen's Mystery Magazine I came across a reference to Ronald Knox's "decalogue for detective fiction," which sounded as though it was a set of rules for writing detective fiction - though one with which I was unfamiliar.   People who read mystery fiction are curious by nature, so I set out to learn a bit about Mr. Knox.

Ronald Knox, as it turns out was a British writer of detective fiction who was practicing his art a full century ago.  He was also, probably much to the disappointment of his Anglican family and forebears, a Catholic priest.  Father Knox was a member of an elite specialized writing group which called itself the "Detection Club."  Other members of the group included Agatha Christie, E.C. Bentley, Dorothy Sayers, and G.K.Chesterton.  (Perhaps Knox was an influence in one of Chesterton's more memorable fictional characters:  Father Brown.)

As  a working writer of detective fiction, Father Knox sought to impose some order and structure on the craft.  He drafted a set of ten rules for himself and his fellow crime fiction writers, a list that some referred to as Knox's "commandments" or his "decalogue" for detective fiction.  Those rules help to define the craft during formative years of the genre, but today most are regarded as outdated and routinely ignored.

Nevertheless, I would like to share them in an effort to give a feel for the forces that molded the adventures and actions of detectives from Sherlock Holmes to Sam Spade and established the early genetic code for today's fictional investigators.

The following are Father Knox's rules for detective fiction, a standard of the times a century ago:

1.  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.

2.  All supernatural or preternatural agencies are rules out as a matter of course.

3.  Not more than one secret room or passage is allowable.

4.  No hitherto undiscovered poisons may be used, nor any appliance which will need a long, scientific explanation at the end.

5.  No Chinaman must figure in the story.

6.  No accident must ever help the detective, nor must he ever have an unaccountable intuition which proves to be right.

7.  The detective must not himself commit the crime.

8.  The detective must not light on any clues which are not instantly produced for the inspection of the reader.

9.  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, slow that of the average reader.

10.  Twin brothers, and doubles generally, must not appear unless we have been duly prepared for them.

In truth, Father Knox's rules did not even survive the "golden age" of detective fiction unscathed.  His fellow member of the Detection Club, Agatha Christie, certainly fractured a couple of them in her 1926 classic, "The Murder of Roger Ackroyd," widely considered one of the best crime novels ever written - and it is unlikely that the "no Chinaman" rule made much sense (beyond being a racist trope) even a century ago.  Charlie Chan would have been appalled!  

Also, I have never interpreted Dr. Watson, the famed aid and biographer of Sherlock Holmes, as being "stupid."  Watson had a medical degree, a background in the military, and a love or writing.  He brought a different perspective to the analysis of the crime, and he helped to humanize the cold, analytical, and often chemically-and-emotionally-impaired Holmes.

Father Knox's rules are an anachronism, but they have been posted here as historical artifacts intended to cast a bit of light on the origins and development of today's fictional detectives.  Someone who is contemplating putting pen to paper to write a mystery story or novel might benefit from getting a feel for the historical footings of the craft.