The detective must be memorable. Clever Out of the ordinary Have a habit, interest or talent

The crime must be significant. usually a murder or a great theft a crime that can not be reversed or made amends for worth detectives time and effort

The criminal must be a worthy opponent. Intellectual Skillful Clever A battle of intellects between the detective and the criminal.

All the suspects, including the criminal, must be presented early in the story. a mental contest exists between the reader and the detective. a “fair play” rule

All the clues discovered by the detective must be made available to the reader. All evidence presented to reader and detective alike Also a “fair play” rule

The solution must appear logical and obvious when the detective explains how the crime was solved. All the information must fit together like a jigsaw puzzle.