The mystery genre is one of the most popular around the world. English crime novelist Agatha Christie has been outsold only by William Shakespeare and the Bible, and police procedurals—a subgenre of detective fiction—are television mainstays.

Why do so many people love seeking clues and solving crimes in fiction? Is it the comfort of seeing questions answered and justice restored—or the thrill of venturing into the shadows and encountering evil from the safety of our couch?

It’s both and more, according to author Joanna Schaffhausen, A96, who has written nine books in the genre, winning the Mystery Writers of America/St. Martin’s Minotaur First Crime Novel Award for her debut in 2016.

The fictional detective of her latest series, Annalisa Vega, takes on stalkers, serial killers, sociopaths, and her own personal ghosts and demons. In the recently released fourth book featuring Vega, All the Way Gone, the Chicago cop turned PI matches wits with a celebrated neurosurgeon who’s also a suspected killer.

“I've just always been attracted to the structure of the mystery and the suspense that's inherent in figuring out who did it,” said Schaffhausen, who studied psychology at Tufts and has been writing mysteries since she was 8 years old. “My favorite part is when I finally get to be like, here’s the big secret I've been keeping from you. Readers want to be taken on a ride, and I love to do that.”

Tufts Now: How would you define a mystery story?

Joanna Schaffhausen: I would say every story is a mystery, in the sense that something will be revealed to you that you don't know at the beginning. 

But in the mystery genre, there must be a crime. It could be a heist, or a kidnapping. Maybe a child has disappeared, and somebody has returned as an adult claiming to be that child, and now it’s like, is it the same person? Maybe a bomb went off in a restaurant, and now we wonder, who put it there and why? How are we going to catch them? 

Suspense, on the other hand, is when we know there's a bomb under that restaurant table, and the two people sitting there having dinner don’t. And we need to know, oh my God, what's going to happen next? Suspense requires that you show readers at least some of your cards, so they know this is a dangerous situation. Mystery is holding everything back and not revealing it until the very end.

I'm generally trying to do a little bit of each. You figure out one piece of the puzzle, but that immediately raises another question. As you're shutting one door, you're opening another. And that keeps the attention going throughout the story until you get to the big reveal.

Are you trying to keep readers from figuring out who committed the crime?

If nobody reading my books suspects anything or figures anything out, I've done a terrible job with my clues. But if everybody gets it or even half the people get it, I've been too obvious. So what I'm looking for is a few people to figure out some of it and to be able to point to the clues that I've left and say, aha, this is how I knew. And that's when I know the clue is doing its job.

The whodunnit is one way to structure a mystery. Then there’s the show Columbo, where you see right at the beginning of every episode who did it. So the tension is, how does Columbo nail them? What will trip up the villain, where did they make their mistake, and how's Columbo going to figure it out? I have that same kind of cat and mouse game between Annalisa and the surgeon in All the Way Gone.

How do you feel about stories where the protagonist turns out to be the killer, as in a certain season of the show You?

I think that's the hardest genre to write, because you're with that person. You’re in their head. And they know they did it, but they’re just not telling you. So often if it’s done clumsily, you get to the end and you just feel lied to, as opposed to tricked in a fun way. It feels like the writer's thumbing their nose at you.

But when you pull it off, the reader can admire the misdirection. In hindsight, you can go back and be like, “Oh, I see what they were saying here. They were kind of admitting that they did it, but I took it another way.” You have to tell the reader without telling them. It takes the highest degree of skill to pull that off.

Often the narrator themself doesn’t know they did it. It’s the Fight Club twist, where the villain is part of their psyche. And people can definitely be in denial about stuff, to the point they develop a split personality. The complexity of the human brain is one reason I decided to study psychology.

Do more people tend to like “cozy” or “hard” mysteries? Why?

I think the biggest genre is the cozies, like Murder She Wrote or the Church Choir Mysteries. Usually they’re set in a small town, with an amateur sleuth, like the local baker. They’re bloodless—the murder usually takes place offscreen, and then it’s more about the characters and the intellectual puzzle to be solved. The victim in a cozy always deserved it, because they were a bad person. And then at the end, the murderer is revealed and justice is restored. 

Often when people turn to their entertainment, they want a happy ending that makes them feel good, because there are enough terrible things happening in the real world. During the pandemic especially, you saw a lot of readers moving towards cozies and lighter genres like romance—nicer, softer stories with fun, funny characters, where nothing upsetting happens. These readers know people can be bad, but don't want to dwell on it personally. They’d like to focus on the good.

But there are also readers for the slashy, bloody mysteries that are super violent and dark, where there's viscera on the walls. We find out who did it, but maybe the protagonist dies, or we don't save the kidnapped person, or the killer get away with the murder or the million dollars. Justice is often not restored, and it's a very dark vision of our society. 

I think people who read these harder mysteries feel like they can arm themselves against bad things in their real life by confronting them in fiction. Maybe it's cathartic in a sense. And some people just really want to look into the darkness of the human soul and contemplate the worst that humanity can be. 

What kind of mysteries do you write?

I’m in the middle. I do like my crimes to feel crime-y. There are some people in my books who definitely represent the abyss. But reality is rarely that simple. You can have somebody who behaves like a sociopath only for short periods of time. Or they're narcissistic and manipulative, but not totally callous, and mostly they follow society’s laws. Is this person a sociopath? If so, does it matter if they’re a net benefit? I don't know.

I also have a lot of characters who are good at heart—who might make mistakes, but they're trying to be a force for good in the world. These usually include the protagonist, like Annalisa. But in All the Way Gone, the sociopath points out to her that he’s saving lives as a surgeon, but in her line of work as a cop, she’s killed people. He forces her to rethink her role in society. Does she have a bad or sociopathic side? Is he right that he’s a better person on the whole?

In my work, justice is mostly restored—but imperfectly. You get an answer, but it may not resolve everything, and it may not feel like justice. Then the question is, what do we do about it? And the answer can vary.

What makes for a truly compelling and satisfying mystery?

Readers should want to know who killed that person, and the reader's window into your story is your protagonist. If the protagonist doesn't care—and care a lot—the reader isn’t going to. 

It should feel like a quest. Even with detective fiction, you want some sort of personal connection. Why is this detective the one solving this mystery, and how is it going to change them? 

Sometimes they’re investigating a family member or someone they know, or they knew the victim. Or maybe they served in the Iraq War and the victim was a fellow veteran. It’s also common to have a detective who’s a loose cannon, or they've been having substance abuse problems, and their boss is like, “We're giving you this last chance to solve this case.” And so that's why they're personally invested. 

If your main character is not on some kind of journey of self-discovery along with their journey of the mystery, it is probably going to feel a little hollow. There should be some character development in which they learn things about themselves. And the reader is also going on this journey and changing somehow.