If the little grey cells are not exercised, they grow the rust.

– Hercule Poirot, The ABC Murders by Agatha Christie

If you are a fan of detective fiction like I am, you are probably familiar with the silhouette above. If not…well…allow me to introduce you to Agatha Christie’s iconic, lovable, and incomparably well-mustached Belgian private detective, Hercule Poirot. Christie introduced Poirot to the world in 1920, and he has since appeared in 33 novels and over 50 short stories. 

Poirot is among my favorite characters in literature and Christie, who remains the best-selling novelist of all-time, is not only my favorite mystery author, but one of my favorite authors of any genre. Indeed, I have a great love of classic mystery novels—a term which includes Victorian-age fiction (think: Sherlock Holmes), as well as stories from the Golden Age of detective fiction (1920s-1930s), and encompasses whodunnits, hard-boiled detectives, arm-chair sleuths, and noir detective fiction.

While the “Queen of Crime” occupies the greatest space on my library shelves, my love of mystery novels dates back much further than my discovery of Christie’s body of work. My first exposure to mystery novels came from The Nancy Drew Mystery Stories by Carolyn Keene. As a young girl, I spent countless hours solving cases alongside Nancy Drew, girl detective. Those experiences provided the foundation for what would later become a great love of classic mysteries in general and whodunnits, in particular. If you’re not familiar, a “whodunnit” (short for “Who has done it?”) is a variety, or subgenre, of detective fiction in which the plot revolves around the mysterious commission of a crime—most often a murder—that the reader is invited to solve alongside the protagonist detective.

I consider a well-crafted whodunnit to be among the greatest literary pleasures. And, in my opinion, when Christie is at her best, there is no one who does it better. Much of the discussion that follows focuses on that particular subgenre but is not exclusive to it, nor is the list of reading recommendations at the end, which includes noir detective fiction, as well as contemporary authors who write classic-style mysteries. That said, here are some reasons to love classic mystery novels:

The Puzzle 

Every whodunnit is a kind of game—a puzzle—from the first page. What you’re being told is every bit as important as what you’re not being told. As a reader, you must understand that. Authors often hide the clues necessary to solve the mystery in plain sight. They also engage in their fair share of artful misdirection and gamble with your ability to make inferences and draw conclusions.

For example, an author may causally divulge certain details about a character’s past or about a particular skill or personality trait that, if explained fully, might out them as the murderer. Instead, they leave you to decide, “Is this a clue? Is there something more about this character that’s not being said, and does that matter, or not?” The author may also put undue emphasis on a certain character’s demeanor, appearance, or circumstances (like impending divorce or money troubles) that make them the most obvious suspect. This is almost always a red-herring…or is it? 

Locked-room murder mysteries, those that feature a fixed group of suspects (e.g., a murder committed on a mostly deserted island, on a train, or a ship at sea), and meta-narratives (a mystery within a mystery or a crime that mirrors another crime committed in a different time and place) have an added level of complexity.

Now, I am not one of those readers who actively tries to solve the puzzle—at least not in any dedicated sort of way. I make guesses and construct theories in my mind as the story progresses, like everyone else, but I don’t take notes. Nor do I engage in any sort of systematic guesswork designed to solve the case. To the contrary. I prefer to get swept up in the story. What is paramount for me is knowing that I am being deceived, that I am involved in a game that I probably—even hopefully—won’t win. That is, I want the author to fool me. That’s where the fun is. 

The Lovable Detective

A lovable—or at least likable—detective is the soul of a good mystery. Since I began this post by talking about Poirot, I’ll continue to use him as a primary example. Poirot is quirky, eccentric, fussy, genteel, and impeccable about his appearance, especially his signature mustachios. But what really makes Poirot lovable—and what makes him and every good literary detective transcend the bounds of time and circumstance—is his keen sense of right and wrong. 

To be sure, lovable detectives do more than solve crimes. They are engaged in the eternal battle between good and evil, for which a rigorous sense of justice and a strong moral code are required. And, indeed, that’s a big part of what keeps us coming back to a good detective series again and again: whatever character flaws our detectives may have, we can always trust them to do the right thing. There’s tremendous comfort in that. It’s also what makes the archetype of the lovable detective endure over time.

The Surprise

As I said above, I don’t read classic mysteries because I want to solve a puzzle. I read them because I love surprises. And I want the ending to be a surprise. Being duped, or artfully deceived, by a clever author is one of the pleasantest experiences I can think of as a reader.

A great example of a surprise ending: Christie’s The Murder of Roger Ackroyd. While this novel isn’t among Christie’s most widely-acclaimed, it is, in my opinion, one of her best. The ending for me was jaw-dropping. I can think of no other work of fiction that left me feeling as gobsmacked as The Murder of Roger Ackroyd. To say that she fooled me is an understatement. I had no clue. In fact, I couldn’t have been more wrong. This, of course, was intentional. 

Once the murderer is revealed, the author takes the time to walk you through the trail of clues that she left you throughout the story, which, of course, you missed (or I missed, clearly) because they were so cleverly hidden. Her way of rubbing your nose in it, perhaps, which I love. This novel is a glorious surprise and receives my highest recommendation.

Recommendations (Alphabetical by Author)

This list is by no means exhaustive. It is a short list of some of my favorite authors/series/individual works, past and present. The contemporary authors listed (Horowitz, Montgomery, and Stevenson) follow in the tradition of classic mysteries. With regard to Christie, these are what I would consider my core recommendations. If you’ve never read Agatha Christie and want to experience her at her best, these are great places to start.

G. K. Chesterton

• The Man Who Was Thursday

Agatha Christie

• The Murder of Roger Ackroyd
• The ABC Murders
• And Then There Were None
• Murder on the Orient Express
• Death on the Nile

Arthur Conan Doyle

• The Hound of the Baskervilles

Anthony Horowitz

• Magpie Murders
• Moonflower Murders
• Marble Hall Murders (currently reading)

Ross Montgomery

• The Murder at World’s End

Georges Simenon

• The Inspector Maigret series

Benjamin Stevenson

• Everyone in My Family Has Killed Someone