Retired NYPD detective Dave Gurney pursues a serial killer in John Verdon’s Let the Devil Sleep.

Did your years in advertising help you write fiction?

They helped mainly by providing lots of exposure to the group dynamics of meetings in which many people were pursuing separate agendas, some open and some hidden. I had lots of opportunities to observe and listen to smart people trying to persuade other smart people to do things their way. It’s good training for writing conflict dialogue. Advertising also accustoms one to revision and editing, which is good practice for responding in useful, rational ways to the revision suggestions of editors.

How did Think of a Number, your first Gurney novel, come about?

For a long time, I had in the back of my mind the image of a trail of footprints in the snow coming to an inexplicable stop, with no evident explanation of where the person who made them had disappeared to. As for the number challenge in the novel, I knew how that could be done, and how unsettling such an experience could be. When all this started coming together in my mind, I knew that I would need an appropriate detective to solve the case, and the necessary elements of Gurney’s personality followed from that.

What influenced you?

The Hound of the Baskervilles contains all the basic elements of mood, setting, background, and plot development—laid out exactly as I would do it if I were teaching a course in how to write such a story. Otherwise, the authors that have influenced me the most are the ones that I most enjoyed reading, such as Reginald Hill, for his elegant style, consistency of tone, and his depiction of highly intelligent people, and Arnaldur Indridason, for the way he interweaves the nature of the crime being investigated with the personal issues in the detective’s life.

Is the Gurneys’ marriage like your own?

Some of the major personality elements are similar. I am an introvert, a thinker, prone to endless analysis, interested in patterns, reasons, and explanations. My wife is a much more immediate experiencer of life. If we were to come upon an unusual flower in the woods, she would focus on its beauty, its color, its delicacy. I would wonder what sort of flower it was, why it was there, why in that spot, why by itself, how it got there. My wife’s orientation is very here-and-now. I often feel that she’s more alive than I am, more in tune with the passing reality of the moment. Madeleine Gurney is like that. But our marriage is also different from the Gurney marriage. For one thing, we laugh a lot more.