Sherlock Holmes. Hercule Poirot. Philip Marlowe. Kurt Wallander. Kinsey Milhone.

When fans talk about their favorite mysteries, they usually name their favorite detective, then mention their favorite stories featuring that character.

Mysteries, more than thrillers or suspense stories, depend on the appeal of their detective hero to keep readers coming back for more. Below are the characteristics I find appealing in a detective and try to include these in the crime-solvers I’ve written about.

Friendship

As a reader, I want to feel like the detective is a friend I am accompanying on a case, someone I am excited to catch up with and learn about their latest adventures. The best description of how to create a detective, or any likable main character, I”ve heard comes from author Louise Penny, creator of Chief Inspector Armande Gamache, who works in the province of Quebec. You can watch the interview she did with CBS Sunday Morning.

Eccentricity

If a detective’s major qualities are “strong”, “brave”, “handsome”, “beautiful”, “charismatic”, or any other in a long list of positive characteristics, I am likely to get bored. The characters I am drawn to aren’t the straight up, forthright detectives. I like the ones with quirks that break the typical hero mold. Sir Arthur Conan Doyle brilliantly combined the heroic elements with eccentric habits in Sherlock Holmes, making him far more interesting. He also tempered Holmes’s superhuman qualities with quirks that brought him down to earth.

Fallibility

A detective should never be correct all the time. That’s not human. But she also can’t blow a clue or a case so badly that the reader thinks she should go into another line of work. It’s a fine line. Readers will accept a detective making minor mistakes, if in the end, he solves the mystery. If he doesn’t solve the mystery, the ending still has to have some kind of satisfying pay-off.

In your opinion, what makes a great detective? Who are your favorites?