In 1936, S.S. Van Dine (author of the Philo Vance mysteries) published an article titled "Twenty Rules for Writing Detective Stories." Some of these rules, for example, 3 and 9 seem rather curious today. Fans of police procedurals know it takes teamwork to find the guilty party. Jack Reacher fans know he is too often irresistible to women who are not looking for a long-term commitment. As for some of the other rules, have they stood the test of time? You be the judge.
1) The reader should have the same opportunity as the detective to solve the crime.
2) No tricks can be played to mislead the reader unless it is also done to the detective by the criminal.
3) The detective should not have a love interest.
4) Neither the detective nor one of the official investigators can turn out to be the criminal.
5) The villain must be found by logical deduction, not luck, accident, or un-motivated confessions.
6) The story must have a detective who also solves the crime (by detection).
7) It must be a murder mystery ("the deader the corpse the better").