The Crime Readers' Association

Rules for Detective Stories – David Beckler

16th January 2015

Monsignor Ronald Knox came up with 10 rules of detective fiction as a preface to Best Detective Stories of 1928-29:

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 ruled out as a matter of course;

3) Not more than one secret room or passage is allowed;

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, below that of the average reader;

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

Tastes in fiction have moved on and these rules no longer apply. We’ve had supernatural killers, psychic detectives, previously unknown killing machines/poisons and more than one Chinese character.

The wide variety of crime fiction available now suggests there are no rules, but I would like to propose a few we could apply.

1/ the detective must have a disastrous romantic life and will often live alone having either never got round to marrying or buggering up their relationships through overwork.

— if the detective has children they will be troubled/a pain/off the rails.

2/ the detective must be a ‘maverick’ who gets up the noses of their superior officers — they are allowed to have had a less stormy earlier career that enabled them to achieve promotion to their current rank.

3/ the sidekick is allowed to be intelligent — and can sometimes be brighter than the detective — but doesn’t outshine his superior when it comes to the nitty-gritty of solving the crime.

4/ the baddy can be an intelligent and complex character and we can see his thoughts and motivations — you are even allowed to follow the crimes from the point of view of the criminal

5/ the baddy shouldn’t be more likeable than the detective — although a ‘good’ baddy can appear in several novels, there are downsides and I’ll examine these in a later post.

6/ although baddies can be of any ethnic group, stereotyping should be avoided.

7/ although many aids to investigation can be used, the skills that the detective brings to the group should be those that lead to the breakthrough

8/ the detective can must suffer setbacks where it looks like the bad guy will win — but the detective will ultimately overcome these.

9/ although the sidekick can succeed where the main detective has failed, a superior officer may never do so.

10/ detectives can be of any rank to head up major investigations

I’m sure I’ve missed out many. Are there any you would like to suggest?


David spent his first eight years living on an agricultural college in rural Ethiopia, where his love of reading developed. After dropping out of university he become a firefighter and later a businessman. He began writing in 2010, working on his first novel in his spare time, a crime thriller called Brotherhood.

He enjoys writing about protagonists with a strong moral code who don’t fit in with conventional society and also enjoy writing about baddies and how they arrived at their fallen state.

When not writing he tries to keep fit, socialise and feed his voracious book habit.

More from David

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