It was Professor Solomon Rosner who sounded the first alarm, though his name would never be linked to the affair except in the secure rooms of a drab office building in downtown Tel Aviv. Gabriel Allon, the legendary but wayward son of Israeli intelligence, would later observe that Rosner was the first asset in the annals of Office history to have proven more useful to them dead than alive. Those who overheard the remark found it uncharacteristically callous but in keeping with the bleak mood that by then had settled over them all.

The backdrop for Rosner’s demise was not Israel, where violent death occurs all too frequently, but the normally tranquil quarter of Amsterdam known as the Old Side. The date was the first Friday in December, and the weather was more suited to early spring than the last days of autumn. It was a day to engage in what the Dutch so fondly refer to as gezelligheid, the pursuit of small pleasures: an aimless stroll through the flower stalls of the Bloemenmarkt, a lager or two in a good bar in the Rembrandtplein, or, for those so inclined, a bit of fine cannabis in the brown coffeehouses of the Haarlemmerstraat. Leave the fretting and the fighting to the hated Americans, stately old Amsterdam murmured that golden late-autumn afternoon. Today we give thanks for having been born blameless and Dutch.

Solomon Rosner did not share the sentiments of his countrymen, but then he seldom did. Though he earned a living as a professor of sociology at the University of Amsterdam, it was Rosner’s Center for European Security Studies that occupied the lion’s share of his time. His legion of detractors saw evidence of deception in the name, for Rosner served not only as the center’s director but was its only scholar in residence. Despite those obvious shortcomings, the center had managed to produce a steady stream of authoritative reports and articles detailing the threat posed to the Netherlands by the rise of militant Islam within its borders. Rosner’s last book, The Islamic Conquest of the West, had argued that Holland was now under a sustained and systematic assault by jihadist Islam. The goal of this assault, he maintained, was to colonize the Netherlands and turn it into a majority Muslim state, where, in the not-too-distant future, Islamic law, or sharia, would reign supreme. The terrorists and the colonizers were two sides of the same coin, he warned, and unless the government took immediate and drastic action, everything the freethinking Dutch held dear would soon be swept away.

The Dutch literary press had been predictably appalled. Hysteria, said one reviewer. Racist claptrap, said another. More than one took pains to note that the views expressed in the book were all the more odious given the fact that Rosner’s grandparents had been rounded up with a hundred thousand other Dutch Jews and sent off to the gas chambers at Auschwitz. All agreed that what the situation required was not hateful rhetoric like Rosner’s but tolerance and dialogue. Rosner stood steadfast in the face of the withering criticism, adopting what one commentator described as the posture of a man with his finger wedged firmly in the dike. Tolerance and dialogue by all means, Rosner responded, but not capitulation. “We Dutch need to put down our Heinekens and hash pipes and wake up,” he snapped during an interview on Dutch television. “Otherwise, we’re going to lose our country.”

The book and surrounding controversy had made Rosner the most vilified and, in some quarters, celebrated man in the country. It had also placed him squarely in the sights of Holland’s homegrown Islamic extremists. Jihadist websites, which Rosner monitored more closely than even the Dutch police, burned with sacred rage over the book, and more than one forecast his imminent execution. An imam in the neighborhood known as the Oud West instructed his flock that “Rosner the Jew must be dealt with harshly” and pleaded for a martyr to step forward and do the job. The feckless Dutch interior minister responded by proposing that Rosner go into hiding, an idea Rosner vigorously refused. He then supplied the minister with a list of ten radicals he regarded as potential assassins. The minister accepted the list without question, for he knew that Rosner’s sources inside Holland’s extremist fringe were in most cases far better than those of the Dutch security services.

At noon on that Friday in December, Rosner was hunched over his computer in the second-floor office of his canal house at Groenburgwal 2A. The house, like Rosner himself, was stubby and wide, and tilted forward at a precarious angle, which some of the neighbors saw as fitting, given the political views of its occupant. If it had one serious drawback it was its location, for it stood not fifty yards from the bell tower of the Zuiderkirk church. The bells tolled mercilessly each day, beginning at the stroke of noon and ending forty-five minutes later. Rosner, sensitive to interruptions and unwanted noise, had been waging a personal jihad against them for years. Classical music, white-noise machines, soundproof headphones—all had proven useless in the face of the onslaught. Sometimes he wondered why they were rung at all. The old church had long ago been turned into a government housing office, a fact that Rosner, a man of considerable faith, saw as a fitting symbol of the Dutch morass. Confronted by an enemy of infinite religious zeal, the secular Dutch had turned their churches into bureaus of the welfare state. A church without faithful, thought Rosner, in a city without God.

At ten minutes past twelve he heard a faint knock and looked up to find Sophie Vanderhaus leaning against the doorjamb with a batch of files clutched to her breast. A former student of Rosner’s, she had come to work for him after completing a graduate degree on the impact of the Holocaust on postwar Dutch society. She was part secretary and research assistant, part nursemaid and surrogate daughter. She kept his office in order and typed the final drafts of all his reports and articles. She was the minder of his impossible schedule and tended to his appalling personal finances. She even saw to his laundry and made certain he remembered to eat. Earlier that morning she had informed him that she was planning to spend a week in Saint-Maarten over the New Year. Rosner, upon hearing the news, had fallen into a profound depression.

“You have an interview with De Telegraaf in an hour,” she said. “Maybe you should have something to eat and focus your thoughts.”

“Are you suggesting my thoughts lack focus, Sophie?”

“I’m suggesting nothing of the sort. It’s just that you’ve been working on that article since five-thirty this morning. You need something more than coffee in your stomach.”

“It’s not that dreadful reporter who called me a Nazi last year?”

“Do you really think I’d let her near you again?” She entered the office and started straightening his desk. “After the interview with De Telegraaf, you go to the NOS studios for an appearance on Radio One. It’s a call-in program, so it’s sure to be lively. Do try not to make any more enemies, Professor Rosner. It’s getting harder and harder to keep track of them all.”

“I’ll try to behave myself, but I’m afraid my forbearance is now gone forever.”

She peered into his coffee cup and pulled a sour face. “Why do you insist on putting out your cigarettes in your coffee?”

“My ashtray was full.”

“Try emptying it from time to time.” She poured the contents of the ashtray into his rubbish bin and removed the plastic liner. “And don’t forget you have the forum this evening at the university.”

Rosner frowned. He was not looking forward to the forum. One of the other panelists was the leader of the European Muslim Association, a group that campaigned openly for the imposition of sharia in Europe and the destruction of the State of Israel. It promised to be a deeply unpleasant evening.

“I’m afraid I’m coming down with a sudden case of leprosy,” he said.

“They’ll insist that you come anyway. You’re the star of the show.”

He stood and stretched his back. “I think I’ll go to Café de Doelen for a coffee and something to eat. Why don’t you have the reporter from De Telegraaf meet me there?”

“Do you really think that’s wise, Professor?”

It was common knowledge in Amsterdam that the famous café on the Staalstraat was his favorite haunt. And Rosner was hardly inconspicuous. Indeed, with his shock of white hair and rumpled tweed wardrobe, he was one of the most recognizable figures in Holland. The geniuses in the Dutch police had once suggested he utilize some crude disguise while in public, an idea Rosner had likened to putting a hat and a false mustache on a hippopotamus and calling it a Dutchman.

“I haven’t been to the Doelen in months.”

“That doesn’t mean it’s any safer.”

“I can’t live my life as a prisoner forever, Sophie.” He gestured toward the window. “Especially on a day like today. Wait until the last possible minute before you tell the reporter from De Telegraaf where I am. That will give me a jump on the jihadists.”

“That isn’t funny, Professor.” She could see there was no talking him out of it. She handed him his mobile phone. “At least take this so you can call me in an emergency.”

Rosner slipped the phone into his pocket and headed downstairs. In the entry hall he pulled on his coat and trademark silk scarf and stepped outside. To his left rose the spire of the Zuiderkirk; to his right, fifty yards along a narrow canal lined with small craft, stood a wooden double drawbridge. The Groenburgwal was a quiet street for the Old Side: no bars or cafés, only a single small hotel that never seemed to have more than a handful of guests. Directly opposite Rosner’s house was the street’s only eyesore, a modern tenement block with a lavender-and-lime pastel exterior. A trio of housepainters dressed in smudged white coveralls was squatting outside the building in a patch of sunlight.

Rosner glanced at the three faces, committing each to memory, before setting off in the direction of the drawbridge. When a sudden gust of wind stirred the bare tree limbs along the embankment, he paused for a moment to bind his scarf more tightly around his neck and watch a plump Vermeer cloud drift slowly overhead. It was then that he noticed one of the painters walking parallel to him along the opposite side of the canal. Short dark hair, a high flat forehead, a heavy brow over small eyes: Rosner, connoisseur of immigrant faces, judged him to be a Moroccan from the Rif Mountains. They arrived at the drawbridge simultaneously. Rosner paused again, this time to light a cigarette he did not want, and watched with relief as the man turned to the left. When he disappeared round the next corner, Rosner headed in the opposite direction toward the Doelen.

He took his time making his way down the Staalstraat, now dawdling in the window of his favorite pastry shop to gaze at that day’s offerings, now sidestepping to avoid being run down by a pretty girl on a bicycle, now pausing to accept a few words of encouragement from a ruddy-faced admirer. He was about to step through the entrance of the café when he felt a tug at his coat sleeve. In the few remaining seconds he had left to live, he would be tormented by the absurd thought that he might have prevented his own murder had he resisted the impulse to turn around. But he did turn around, because that is what one does on a glorious December afternoon in Amsterdam when one is summoned in the street by a stranger.

He saw the gun only in the abstract. In the narrow street the shots reverberated like cannon fire. He collapsed onto the cobblestones and watched helplessly as his killer drew a long knife from the inside of his coveralls. The slaughter was ritual, just as the imams had decreed it should be. No one intervened—hardly surprising, thought Rosner, for intervention would have been intolerant—and no one thought to comfort him as he lay dying. Only the bells spoke to him. A church without faithful, they seemed to be saying, in a city without God.

Q. The Secret Servant is your tenth novel. It's both deeply provocative and wildly entertaining. How do you walk that fine line in your work?

I tend to think it comes quite naturally to me. I've always felt that there are two writers living inside me, one with more literary leanings and another who is unrepentantly commercial. These two engage in an annual struggle for supremacy, and the result in recent years has been The Messenger, The Confessor, and A Death in Vienna, novels of entertainment that deal with terribly important topics of today and the past. I like to think of myself as a serious writer who works in the thriller mode.

Q. The Secret Servant moves at a blistering clip from beginning to end. Did you consciously try to write a more up–tempo book?

I didn't in fact. When I begin a novel, I try to have as few preconceived notions as possible. I want to bring the characters to life on the page and then let them lead me by the hand. But there is definitely a ticking clock in the book, with the life of an extraordinary young woman, and perhaps even the fate of a nation, hanging in the balance. It means the characters have to make decisions of great moral significance under conditions of extreme time pressure. It also means that the novel plunges forward at a breathless pace, particularly toward the end.

Q. You speak of characters having to make decisions of moral significance under difficult conditions, and of course that would apply to Gabriel Allon, the hero of your last seven novels. Tell me about him.

It's probably accurate to say that no one has been battling Arab and Islamic terror longer than Gabriel Allon. In 1972 he was a promising art student at Jerusalem's prestigious Bezalel Academy of Art, when he was recruited by Israeli intelligence to hunt down and kill the Palestinian terrorists responsible for the massacre of Israeli athletes at the Munich Olympics. He's worked on and off for Israeli intelligence ever since. He also happens to be one of the world's finest restorers of Old Master paintings. As The Secret Servant opens, he's just finished restoring a painting by Giovanni Bellini for the Vatican. When he returns to his apartment in Jerusalem, he finds Ari Shamron, Israel's spymaster and his own mentor, waiting with another assignment. It's an assignment that will take him back to Europe, to Amsterdam to be precise, where an asset of Israeli intelligence has been brutally murdered by a Muslim immigrant.

Q. The murder scene is hauntingly reminiscent of the killing of the Dutch filmmaker Theo van Gogh in Amsterdam in November 2004. I assume the echo is intentional?

Of course. In many respects, the death of Theo van Gogh was Europe's miniature 9/11. It sent shock waves through the Netherlands and the rest of Europe. It was a violent wake–up call, as was the rioting that swept France during the autumn of 2005. Many European countries now contain large Muslim populations that, for the most part, have not been properly integrated. Many of the young men in these Muslim communities are unemployed and angry. They're fed a steady diet of hatred by their imams and the Internet. They're trapped between two worlds, the world of radical Islam on the one hand and the secular, tolerant West on the other, and all too often they succumb to the siren song of terrorist recruiters.

Q. You write in the book that "Europe is receding quietly into history. It's old and tired, and its young are so pessimistic about the prospects of the future they refuse to have enough children to ensure their own survival. They believe in nothing but their thirty–five–hour workweek and their August vacation." Are things really that bad?

Those were the rather gloomy observations of a longtime character in the series named Eli Lavon, but as someone who loves Europe and who has watched it change dramatically over the last twenty years, I would tend to agree. While it's a risk to generalize, I do think that Europe has lost its way a bit; without question it is facing a looming demographic crisis. In virtually all the countries of Western Europe, the birthrate of the native population is below replacement level, while the Muslim population is increasing rapidly. Sometime in the very near future, Europe will have to confront these facts and make some difficult decisions about its identity. That process is already under way in France, Denmark, and Britain. I hope it is a peaceful process. I'm not at all sure it will be.

Q. One epigraph of The Secret Servant quotes from the historian Bernard Lewis: "On present demographic trends, by the end of the twenty–first century at the latest, Europe will be Muslim." If that comes to pass, what will be the consequences for Europe and the United States?

Profound, to put it mildly. I know for a fact that U.S. intelligence agencies are already thinking about the ramifications of a "Muslim" Europe for U.S. foreign policy. In the short term, however, the restive Muslim populations of Europe provide a fertile breeding ground for terrorism, and that's the backdrop of The Secret Servant.

Without giving away too much of the plot: The book deals with a conspiracy by al–Qaeda and a little–known group of Egyptian extremists to kidnap the daughter of the American ambassador to London. The goal of this plot is to force the United States to release an Egyptian cleric jailed on terrorism charges. It sounds frighteningly plausible. I was discussing it with a friend who works for the CIA. He nodded and said, "Well, that's certainly realistic." Obviously, it's something that I hope never comes to pass.

Q. By now most people know that Osama bin Laden is Saudi, but do they realize how Egyptian al–Qaeda is?

Many people don't know that. Egypt is indeed the heartland of Islamic extremism, and Egyptians are a major component of al–Qaeda. Ayman al–Zawahiri, the number–two man in the organization and, some would say, the real brains behind it, is an Egyptian terrorist leader who spent many years trying to bring down the government of Hosni Mubarak. It's still one of al–Qaeda's ultimate goals, though for now they're focused on what they call the "far enemy," meaning us.

Q. A central theme of the novel is the morality of torture and the practice known as "extraordinary rendition"—taking known or suspected terrorists from one country and transferring them in secret to Middle Eastern countries—Jordan, Syria, Saudi Arabia, Egypt—for questioning. Why did you choose to deal with this in the book?

For me, the rendition program has been one of the most troubling aspects of U.S. response to the attacks of 9/11—and mind you, this is coming from someone who believes Islamic extremism and terrorism are grave threats to American security and must be dealt with harshly. But the regimes you mentioned are some of the most repressive in the world. I believe they've helped create and foster the problem of terrorism by attempting to deflect the anger of their people outward to America and Israel. Ultimately, they're part of the problem, not part of the solution. Borrowing their torture chambers is one of the big moral lapses of our response to the attacks of 9/11.

Q. If the president of the United States had asked Gabriel Allon for advice on September 12, 2001, what would Gabriel have said?

He would have warned the president about the terrible price of climbing into the sewer with terrorists and fighting them on their terms. He would have told the president that the fight against terrorism was not only morally just but also morally imperative. But he would have cautioned the president not to resort to practices that don't look terribly flattering with the passage of time. A few years ago I wrote a book called A Death in Vienna. It dealt with one of the more unsavory aspects of the Cold War: the CIA's use of Nazi war criminals as paid assets. The novel was really a private plea to policy makers not to take similar morally questionable steps in the war against terrorism.

Q. The Secret Servant contains some disturbing descriptions and accounts of torture as practiced by the Egyptian secret police. Are the accounts in your book based on fact?

Unfortunately, they are. I did a considerable amount of research on the practices of the Egyptian security services, and I heard first–hand accounts of their work when I was based in Cairo in the 1980s as a correspondent for United Press International.

Q. That experience must have been very helpful to you when you were working on this book.

Very much so. I interviewed Islamic militants during that period, men who, I assume, went on to become members of al–Qaeda. They made it clear to me then what they wanted to do—they said they wanted to destroy us—and I believed they were serious. During the late eighties and early nineties, I told anyone who would listen that we would one day face a grave threat from militant Islam, and my fears were proven correct.

Q. One of the most compelling characters of The Messenger was Sarah Bancroft. Why did you decide to use her again?

"Back by popular demand" is probably the best way to put. Everyone loved Sarah the moment I handed in the first draft of The Messenger, and the response I received from readers after publication was also overwhelmingly positive. I needed a CIA component to Gabriel's team in The Secret Servant, and she was a perfect fit.

Q. The book is set in a number of cities: Amsterdam, London, Copenhagen, Cairo, and Jerusalem, to name a few. Judging from the flawless depictions and other evidence of the amount of research you must have done, I guess you didn't spend the entire summer on that cattle ranch in the hills of Umbria.

As much as I would have liked to, the answer is no. I returned to the States in July and spent a month on a book tour, then went back to Europe to start researching my next book. My family jokingly referred to it as the "Summer Euroterror Tour of 2006." The first stop was London, where MI5 and Scotland Yard had just broken up the plot to bomb transatlantic jetliners with liquid explosives. Then it was on to Amsterdam and Denmark. My children are old enough to help out now. When their teachers ask them what they did on their summer vacation, they say they spent it helping their father pick out places to kill people.