As the author of three novels involving serial murder, I’ve been asked to speculate on the reasons for the durable popularity of this grisly subject matter.

What indeed is it about this particular sort of crime that rivets our attention? More curiously, what makes this form of absolute horror an addictive form of literary diversion?

Perhaps there are as many answers as there are devotees of the genre. But there’s one that I find especially persuasive. It concerns that experience of diversion I just mentioned. To get to the heart of it, we need to ask one additional question, a crucial one: Diversion from what?

Consider the nature of the beast -- the classic serial murderer, the sociopath with zero empathy, the pure predator who kills to feel alive. We’re not talking about someone who may be willing to employ murder as a crude means to an end -- a way to eliminate some obstacle to the acquisition of, say, a large inheritance or a neighborhood heroin franchise or a lucrative construction contract.

What logic there is in the behavior of the serial murderer is the logic of darkness and destruction. Serial murder is about the act of murder. In its purest form, the murder is not secondary to any sane goal. It is murder for the sake of murder, killing for the pleasure of killing. It’s about the power and excitement of summoning death itself.

This might appear at first glance odd material for casual airplane and beach reading. And yet, there’s a long human history of seeking diversion via immersion in the most dreadful fantasies. So-called fairy tales are an instructive example. We humans have a deep interest in monsters and horror. Picturing fantastical threats seems to be a basic function of our brains.

This dark faculty of imagination is much misunderstood and maligned, occupied as it is with fictional misery, as opposed to “reality”. But imagination, at its root, is intensely practical. It evolved in us as a tool for examining the likely outcomes of possible courses of action, a way of literally “looking at” potential risks and rewards before choosing the most advantageous path. Our ability to imagine terrible things can prepare us to meet real dangers in the future, or persuade us to walk in a different direction. But like many human capabilities, it has its downsides.

We can, for example, envision monsters we cannot escape. It’s a terrible predicament, this human capacity -- one might even be tempted to say proclivity -- for envisioning overwhelming problems.

This, I believe, is where fiction comes to the rescue. Fiction can alleviate the sense of terror and helplessness, by organizing our direst fantasies in a structure that provides a reassuring solution. Fiction can thus offer us a reassuring kind of order. Fiction can put the tiger in the cage.

This is a function of enormous emotional value. As human beings, we have the ability to imagine the worst. The devouring monster in the closet against which reason withers, hope dies, and only a paralyzing fear remains.

Fear of what exactly?

We are unique among animals in one way. Long before it happens, we know we’re going to die. And we know we’re ultimately helpless in the face of that reality. I think it’s impossible to overstate the impact of that one fact of human life. But how does it relate to our enduring fascination with serial murder?

In one important way. To me, the serial killer represents the most fearsome embodiment of death itself. The grim reaper. Intellect without heart. Eyes without empathy. The serial killer represents a death that does not respond to pleas for mercy -- a death that has its own agenda, coming for us in its own time, driven by its own inexorable logic. The ultimate serial predator. The ultimate monster in the closet.

If that’s true, if that’s the connection, if that’s the resonance we feel, why should we want to read serial killer novels? Why read about the thing that terrifies us?

Maybe for the simplest of all reasons: the detective wins. In the world of the novel, the heartless killer is defeated. In the world of the novel, death loses in the end. Our worst fear is, for a moment, laid to rest. So, perhaps it makes a kind of perverse sense that the genre that has the metaphorical power to conjure up our greatest fear also has the power to offer us the greatest relief -- fleeting though that relief may be.

Will these frightening novels always have this special power?

That’s difficult to say. What I am sure of, however, is that any literary form that provides a route to victory over the specter of death will find a receptive audience.

In the grandest terms, I’d like to believe that what I’m doing as a thriller author is dealing death a small defeat. Even if it’s only temporary. Even if it’s just on paper.

John Verdon's Let the Devil Sleep publishes on July 24 from Crown.