The response has been tremendous, it’s true. It’s been very flattering and I’m grateful for it. I think there are a couple of things going on.

First, the story touches on ordinary, universal emotions about family and children. It raises a whole slew of questions that will feel awfully familiar to every parent and every family: Why do children behave as they do? How much is “hardwired” in their nature, how much is shaped by nurture? Why do good families sometimes produce bad children, or at least flawed children? What should parents do when a child begins to show signs of trouble? How far should you go in defending your child? Of course most parents will never be faced with the life-or-death stakes the Barbers confront in Defending Jacob, but I think all parents will see traces of their own hopes and anxieties in Laurie and Andy Barber.

I have two kids myself, boys who are seven and ten years old as I write this, so I understand how vulnerable our children make us, emotionally. We all want good things for our children. We all want to be good parents, make good decisions, do the right thing. And of course we all want to feel proud of our kids. But for a certain percentage of us, an unlucky few, it won’t work out that way. Inevitably some good parents — smart, well-meaning, conscientious people who do everything right — will see their kids wander into trouble anyway. It’s a risk you take when you have kids, and every parent knows it.

The other thing that people are responding to in Defending Jacob, I think, is that it is not simply a mystery or a thriller or a courtroom drama, nor is it just a “literary” drama about a family in crisis. It is all these things — at least I hope it is. That is why the book is able to appeal to readers as different as Lee Child and Nicholas Sparks, two authors who are poles apart in their writing. (I suspect this is the first time the names Lee Child and Nicholas Sparks have ever appeared in the same sentence!) At some point publishers and booksellers seem to have decided on very rigid categories for novels, Mystery/Suspense, Romance, Literary Fiction, and so on. Of course many writers bristle at these categories. But I like to think that Defending Jacob is the sort of book that can jump the tracks, so to speak. I think fans of Lee Child and Nicholas Sparks — and Anna Quindlen and John Grisham and many others — will all enjoy it.

What was your motivation in writing a thriller about a family in crisis?

I’d written a couple of novels before Defending Jacob that were more traditional crime novels, which is to say they were set entirely in the world of cops and criminals. (At least that is how they were pigeonholed.) I was an assistant district attorney for several years, and at the time I wrote those books the crime world was something I thought about quite a lot. By the time I started Defending Jacob, though, I had left the DA’s office and become a full-time writer — and, most importantly, a father. I remember sitting down with my editor, Kate Miciak, to discuss what to write next, for book three. We talked about writing something that was closer to my heart, a book that reflected my own life a little more, given how my life had changed. So Defending Jacob began as a way to bring together these two worlds, these two parts of my life, the world of criminal law and especially of prosecutors, and the world of raising kids in the suburbs. (I suppose this would be the time to point out that my own two boys have nothing at all to do with Jacob Barber. The only crime my kids have ever committed is not listening to their father, though they are shameless repeat offenders.)

Has your experience working as an Assistant District Attorney shaped DEFENDING JACOB?

Absolutely. I was an Assistant DA for several years in the 1990s, and many of the details in the book grew directly out of that experience. The prosecutor’s office portrayed in Defending Jacob, the Middlesex County (Massachusetts) DA’s Office, is the same one where I worked — though the characters themselves are entirely fictional. (Yes, really.) And Jacob’s murder trial, which is the main set piece of the book, is described in as much authentic detail as good storytelling allows.

But the book shows the influence of my years as a prosecutor in less obvious ways, too, I think. Those years as an ADA simply made me more aware of crime, of its danger and pervasiveness and, I admit, its drama. To put it simply, I just spent a lot of years thinking about crime and criminals. In fact I remember, when I first left the DA’s office, how strange it seemed that no one else ever thought about crime very much. My days had been filled with every kind of crime, at least with the lawyers’ work of sorting out what to do about it after the fact. My colleagues and I talked about our cases constantly, about this or that defendant or witness or cop or lawyer. And of course even after I left the DA’s office I continued to write novels about crime. But to most ordinary people, certainly to my neighbors in the comfortable town where I was living, crime was “out there,” it was theoretical. Statistically, they were unlikely ever to be touched by it directly. They were innocent, in a sense. Not naive, but innocent. As a writer — particularly as a crime writer searching for interesting new settings — that is a promising opportunity. Every writer draws on his various experiences, I think. My experiences stirred together the worlds of criminal law and the world of young families. The result is Defending Jacob.

In the book, it’s not a spoiler to say that the Barber family, respected members of the community, are faced with the very real prospect of losing everything when their son Jacob is accused of a vicious crime. How accurate is the portrayal of their plight?

Thankfully, I don’t know. In my work as a prosecutor, I had virtually no contact with defendants’ families. Prosecutors do spend lots of time with victims and their families, obviously, but victimhood does not carry the same social stigma.

Still, I remember looking across the courtroom at the defendants’ families sitting in the front row of the spectators’ gallery, particularly the parents. Some were belligerent, eyes narrowed, jaws firm; they defended their children to the hilt, never seemed to admit the slightest doubt about their son’s innocence (it was usually a son) or the justice of releasing him back into the public. Others were plainly suffering; their son was caught in the teeth of the criminal justice system and there was simply nothing they could do to help him.

The plight of defendants’ parents came home to me most vividly in a famous case prosecuted well after I’d left the DA’s office. (I won’t name it here.) In that case the defendant’s parents were both lawyers, the mother a prosecutor, the father a criminal defense attorney. Throughout a long trial that was splashed all over the newspapers and TV, these two lawyer-parents never spoke a word in public, never reacted to anything in court. They sat stone-faced, unwilling to give the jury or the media anything at all. Whatever their son might have done, it was impossible not to feel for them. Bad things do happen to good people, after all.

DEFENDING JACOB explores the emerging science of behavioral genetics and neurocriminology — the notion that, as a predictor of criminal behavior, nature may indeed be as significant as nurture. Can you tell us about your research into this, the legal and ethical implications and what personal conclusions you came away with?

I’m not a scientist, but I find this emerging science of “behavioral genetics” really fascinating. Essentially the idea is that physical factors — very specific genetic mutations or malfunctioning of the brain — may create a biological tendency toward violence. This is cutting-edge stuff. We simply haven’t had the tools to study these biological triggers for long. The effort to map the human genome began only twenty years ago and was completed less than ten years ago. So we still have a lot to learn.

Already it is clear that the implications for science and medicine are enormous and have been written about quite a bit. But we’ve heard less about what it might mean for law and crime. Partly that is because the science is still developing. It is one thing to identify a genetic mutation; it is a heck of a lot harder to establish a link between that mutation and people’s actual behavior.

But I think we’ve also avoided the subject because it makes us so uncomfortable. Our discussions of the nature/nurture question have always tilted in the direction of nurture. We like to believe we can be anything we want to be. We like to believe we are independent, free-willed, masters of our own fate. The suggestion that we might be wrong — that we are hardwired to behave in certain ways, that nurture may play a larger role than we ever imagined — challenges a lot of assumptions we make about ourselves. What if we are not free but fated — by genetic inheritance or by physical damage to our brains — to behave in violent ways? What if we have always favored the “nurture” side of the equation for the simple reason that we have never been able to study the “nature” side until now?

The haunting idea of a “murder gene” or a “warrior gene” is particularly subversive in criminal cases. The law generally presumes we are responsible for our own conduct. It presumes we decide to commit crimes. Defendants who cannot actually decide to misbehave — because they are insane or under age, most commonly — are considered less culpable. Is the “murder gene” a new category, a new exception to the general rule? Rather than “not guilty by reason of insanity,” will we someday be saying “not guilty by reason of an inherited tendency to violence”?

To my knowledge, the “murder gene” defense has never worked in court in this country, though it has been offered in mitigation at sentencing. But in Italy last year, a man convicted of what would, in the U.S., be called second-degree murder or manslaughter had his 9-year sentence reduced on appeal on the grounds that he exhibited genetic mutations and brain abnormalities that caused him to be violent. One of the abnormalities the Italian defendant had was a mutation in his DNA called “MAOA Knockout” — precisely the “murder gene” that Jacob Barber inherits.

It is important to keep all this in perspective. The phrase “murder gene” is shorthand. It is a convenient way of talking about a very complex subject. But it is wrong to assume that anyone who inherits this gene will become a murderer or will become violent or aggressive at all. As the Barber family learns in Defending Jacob, there is no single cause of human behavior. Our actions are influenced by a thousand things. We are not robots, programmed to act in a few fixed and predictable ways. Human behavior is the result of our genes and our environment both — nature and nurture — in an unfathomably complex interaction. It is important to remember that.

But for futurists and novelists, think of the implications of behavioral genetics. What if we tested children for the “warrior gene” when they entered kindergarten? Should students who test positive be monitored or tracked differently, for the protection of their classmates? Should the children of violent criminals be tested? What if a pregnant mother could be told her unborn child carries this dangerous genetic marker? Should the police be informed that certain citizens are genetically predisposed to become violent, to protect everyone else? On the other hand, there is a long and bloody history of this sort of thinking. The lethal danger of “eugenics” haunts all our discussions — and rightly so.

Setting aside the science itself, it is also worth thinking about how storytellers use this sort of cool cutting-edge science, novelists in particular. Crime stories have been obsessed with forensic science for a long time now. There are many, many variants on the “CSI”-type of story — “Aha! A hair follicle at the crime scene! And a carpet fiber!” I’ve always found this trend unfortunate. The real power of crime stories is what they tell us about ourselves as human beings. To get caught up in the technical details of forensic science is to miss the forest for the trees. We love crime stories — and have loved them for a couple thousand years now — because they are about people, not because they are about science. The Greeks did not need to understand DNA to understand the tragedy of Oedipus, the first detective.

There is a role for science and forensics in crime stories, but in Defending Jacob I consciously avoided getting bogged down in it. Stories — good stories, classic stories — are about people. Otherwise they become dated very quickly as today’s cutting-edge science becomes routine and then old hat. Fingerprints were a cutting-edge science once, too, but today a story that turned on a fingerprint — “aha!” — would seem hopelessly old-fashioned and boring. (In fact, I consciously chose to use a fingerprint as one piece of evidence in Defending Jacob because it has a classic, retro feel.) Someday our grandchildren will see old reruns of “CSI” and laugh, or yawn. But they’ll still be reading about Oedipus. And hopefully about Jacob Barber, too.

The extreme situation that Jacob’s parents are faced with will make readers question how they would react in a similar situation. Do you think writing DEFENDING JACOB has changed you as a parent and husband?

I think it’s very hard for any of us to know how we might react in Andy or Laurie Barber’s place. It’s such an extreme situation. Personally, I suspect I have a bit of both Andy and Laurie in me. All fictional characters are to some extent a projection of aspects of the novelist’s own consciousness. How could they not be? I am intensely loyal, as Andy is, and I can easily imagine myself standing by my son right or wrong, as Andy does. It’s hard for me to imagine anything that could ever, ever separate me from my child. At the same time, like a lot novelists I tend to stand back a little, to watch from a corner of the room, to see things from a little distance. I’m sure that, like Laurie, I would have to look at the mounting evidence and begin to wonder, “What should we do … if?”

Has writing the novel changed me? Well, it’s certainly been a sobering exercise to imagine my own worst fears in such vivid, excruciating detail. But there is a payoff: it is useful to be reminded that a family is a fragile thing. And that is the power of novels, isn’t it? You get to live for a while as another person, you step right into his consciousness, his thought-stream, you get to feel what it is like to be someone else. I suspect that, after being Andy Barber for a while, readers will return to their own families with fresh eyes. I certainly hope so, anyway. Tolstoy was wrong: happy families are not all alike. If you’re lucky enough to have one, as I do, be thankful. It can all be taken from you.

As a parent, do you think it’s really ever possible to be completely objective and unbiased when it comes to your kids?

Completely objective and unbiased, no. But I think for every parent there are moments when you see your child at a little distance, with a little objectivity. When the kid misbehaves or shows bad judgment, or just surprises you by doing something unexpected. Every parent has moments where you think, “This kid really is his own person — another human being, not just an extension of myself.” Those moments feel a little sad, actually. You feel a little sense of separation, a precursor of the Big Separation that all parents have to steel themselves for, when the child finally leaves the family to go off into the world as a young adult. But completely unbiased? No way. We’re all like Andy Barber, deep down. We see with our hearts.

Today’s generation of parents is known for closely monitoring our children — including social media, which plays an important role in the case against Jacob Barber. As a parent with first-hand experience of how dangerous this world can be, how do you balance trust and the responsibility to keep your children safe?

It’s a real challenge for all parents today. It’s not just social media, either. It’s the entire internet. Every web-connected device is a portal to all sorts of unhealthy material, including hardcore pornography. Parents have to be very, very careful. At the same time, you have to trust and respect your kids. It’s a very hard balance to strike. In Defending Jacob, ordinary parents are shocked at what they find when they finally do check out what their son has been up to on the internet. I think that is probably a common experience, or would be if more parents were more alert to the danger.

On the other hand, kids have always kept secrets from their parents. They have always passed notes in class and whispered on the phone. Social media just introduce a new and powerful way for kids to do what they’ve always done.

What certainly does change with social media is the broadcast aspect of communication via Facebook or Twitter or whatever will come next. Rather than the one-to-one communication of a note or a phone call or even (gasp!) a live, in-person conversation, social media send the message to a large, unseen audience and things tend to snowball very quickly online.

Not sure there are any easy answers here. Trust your kids, but watch them. Use and understand the same online tools they are using. And pray like hell that it all works out.

As for our generation of hovering, micromanaging “helicopter parents,” this is another aspect of the nature/nurture question, isn’t it? Implicit in all our hovering is the assumption that it matters — that good parenting produces good kids. The idea of a “murder gene” — or let’s say, an “aggressiveness gene” — contradicts that. I certainly don’t mean to suggest that “helicopter parenting” is bad parenting. There are many different styles of parenting, many ways to be a good parent. A friend of mine, a doctor, has a saying: “Intelligent, well-meaning parents can’t make a bad decision.” I like to think that’s true. But who knows? It’s likely that our kids will make fun of their helicopter parents someday, just as we make fun of our own disengaged, chain-smoking, fatty-diet, no-seat-belts, no-bike-helmets generation of parents.

Was DEFENDING JACOB based on any real cases that you worked on?

No. There were several kid-on-kid homicides that took place during the writing, in Massachusetts where I live and elsewhere, but honestly there was no particular case that inspired it. In fact, I have been surprised at how often people say to me, “Your book reminds me of such-and-such.” These cases keep coming up all over the country. It happens over and over, and we are shocked every time. For parents, some crimes just hit close to home, I suppose. That our kids live in the same dangerous world we do — that their world may actually be more dangerous — is a troubling thought.

What do you want the reader to ponder when they turn the last page?

I wouldn’t tell readers what to think. I’m just a storyteller. What the story means is up to each reader. Suffice it to say, I hope everyone sees a little of themselves in the Barber family. We all grow up in families of one kind or another. What the Barbers endure will not be familiar to most readers, I hope, but the little shiver readers experience may have a familiar feel. When you think about it, the Barbers’ troubles are not so different from any other family’s — only much, much bigger.A Conversation with William Landay

Interview by Tess Taylor

Andy Barber, the narrator and protagonist in your book, is a guy who went to Yale and to work in a DA's office. You also attended Yale before becoming a DA. Any veiled autobiography here?

Well, certainly I drew on aspects of my own life as I was creating Andy, but there's no "autobiography." I never thought of Andy as a stand-in for myself, even when writing in his voice in first person — when I was pretending to be him. Actually, Andy began as an amalgam of several respected, soft-spoken, older trial lawyers whom I met during my years as an assistant D.A. But a funny thing happens as you write: you begin with a real-life model for a character, but you change him a little, then a little more, and at some point the model falls away and the character emerges as his own person. It's a mysterious fission. In the end, Andy did not resemble any of the lawyers I had in mind when I started.

But Andy is my creation and inevitably aspects of him reflect me, probably in ways more intimate than just biography. For all his fluency in the courtroom, he's essentially an introvert, as I am. He is doggedly loyal, especially in his determination not to abandon his son. Does that make him a good father or a good person? I don't know. Readers will have to decide for themselves. But I like him for it. Wouldn't we all like to think our dads (or spouses or friends) would stand by us, no matter what?

Jacob Barber, the accused murderer in your book, is a teenager, an 8th grader who is being tried as an adult. Are 8th graders currently tried this way in Massachusetts? And why that age? What makes a teenager a rich protagonist?

Yes, this is the current law. In Massachusetts, all defendants age 14 or older accused of first-degree murder are tried as adults, and if convicted they receive a mandatory sentence of life without parole.

The trial sequence in Defending Jacob is rendered about as accurately as good storytelling allows. Obviously there is compression for pace. Real trials move slowly. Technical rules play a larger part. But I didn't have to depart from reality much. Criminal trials are inherently theatrical — a live dramatic performance leading to the climax of a verdict. That is why writers, practically since Plato, have always been drawn to them.

Choosing to write about a teenager was a personal as well as creative decision. I have two boys myself. They are 8 and 10 years old. Those kids mean everything to me. My books have always been about family, but with Defending Jacob I wanted to write something even closer to my heart, something that would bring together the crime world of my D.A. years and the life that I live now, of being a young father. (I should point out, by the way, that my kids are perfectly well behaved. Neither has been accused of murder, at least! Disturbing the peace, maybe. )

And adolescence is such a powerful, universal experience. Many readers will have a teenager in their lives now or remember the turmoil of being one. It's a difficult time for parents and kids both — full of secrets, hormones, drama. High emotion is a storyteller's red meat.

You seem attuned Jacob's uneasy adolescent ways, particularly how he uses media — Twitter, Facebook, blogging. What about the technological revolution — especially as it's impacting young people — fascinates you?

I'm a bit of a tech geek myself. I use all these new media. Some I enjoy more than others. (Facebook creeps me out, honestly.) But I have no doubt that, whatever you may think of the "social web," it is hard to overstate its influence on our daily lives, especially the lives of young people. These "new media" are now a routine part of how we relate to one another. They tend, ironically, to make us feel less connected. It's fitting that we call them media: they mediate, they add a filter between us that can leave us feeling isolated.

To me, there is nothing inherently frightening in kids using these new ways of communicating. Trading gossip on Facebook isn't all that different from gossiping on the phone or passing notes in class. There is one key difference, though: the reach and anonymity of the web — where a kid sitting alone in his bedroom, feeling emboldened, typing on a laptop, can reach a very large audience — creates the risk of disaster. Ordinary bullying becomes cyber-bullying. Teasing becomes vicious. Kids do get hurt.

In Defending Jacob, the Barbers are shocked to find what their son Jacob has been up to on the Internet. I don't want readers to be freaked out by that aspect of the story, but if they take it as a wake-up call, an opportunity to figure out what their kids are doing online, then that is a good thing.

Your book also has a science angle — exploring something the book calls "the murder gene." When you're crafting evidence for a fictional piece, what kinds of research do you do into, say, contemporary uses of science in the courtroom?

The science in the novel is a very real area of research. It's usually called behavioral genetics — the study of how genes affect behavior.

The subject tends to alarm people. It's important to keep this emerging science in perspective. Genes are not simple triggers. No one is hardwired to commit murder or any other crime. Our actions are always the result of stupendously complex gene-environment interactions, and environment is likely to remain the more important influence by far. Nurture, not nature. At the same time, having mapped the human genome, we are entering a new era in which we finally have real insight into the "nature" side of the debate.

The specific genetic variation mentioned in Defending Jacob, a mutation of the MAOA gene, is quite real. Linked to aggressive behavior, it has been called the "warrior gene." A few details about it were elided to serve the story, but it is generally described accurately.

I learn as much as I can about any scientific issue I use in my books, but I am not a scientist. When push comes to shove, I do fudge facts as necessary to tell a good story. I think the job of novelists — and all artists, I suppose — is not to portray the latest science with 100% accuracy. It is to begin to think about what science means for ordinary people in human terms. Raising questions about science, about its implications for society — that is as important as science itself. We still can't build a human out of parts, but we haven't stopped thinking about Frankenstein. In its own way, Defending Jacob raises similar questions.

Defending Jacob is more psychologically upsetting than actually gory. Act for act, there's less physical violence in this book than in many crime novels — only scattered incidents of bloodshed, suspected but unconfirmed murders. Nevertheless, the weight of what might have happened is heavy. Do you have a philosophy about how much actual violence to show versus how much to imply?

It's simple: I have no problem with storytellers using violence (or sex or profanity) so long as it is true to the story. The trouble comes in using cheap violence — to give an easy thrill or to indulge people's worst impulses (bloodlust, misogyny). It's phony suspense. In Defending Jacob, I didn't need to show much. The foreboding actually reflects how little violence the reader sees.

I was impressed with the book's flow. I devoured it in one gulp, so to speak. Can you let us into your craft? How do you plot a thriller?

Thank you. Well, I outline fanatically. I am a long thinker and a slow writer, though I am trying to get faster. (My children have an unfortunate habit of eating. And outgrowing their clothes. Hence the need to produce more books!) Probably careful plotting reflects my personality. I am meticulous by nature. I can't imagine speed-writing anything that happens to pop into my head.

As for my typical workday, it really depends. Early on, when I am still trying to figure out what my story is, my days can be unstructured and frankly very frustrating. Toward the end, words tend to come in waves and the days get very long. The last fifty pages of Defending Jacob were written in one long sprint over the course of only a few days. I work exclusively on a computer — my outlines, notes and drafts rarely ever get printed out. I often work in coffee shops. So you may see me one day, hunched over a laptop, typing madly with two fingers or (more likely) staring into space.

Who are the writers you are reading now? What recent books inspire you?

One of the best parts of becoming a writer is that I have the privilege of reading advance copies of books before they are published. One of these, The Orphan Master's Son by Adam Johnson*, absolutely blew me away. It's out in January and I hope lots of people read it. Set in North Korea, it is the story of Pak Jun Do, a man who rises from miserable roots to stand beside the "Dear Leader" himself, Kim Jong-il. It is an epic story — a big book in every sense — and utterly riveting. Kim Jong-il's death has put North Korea in the headlines lately. I hope the increased level of interest somehow helps Adam's amazing novel find the audience it deserves.