THE SOMETIMES-SOLVENT firm of Isherwood Fine Arts had once occupied a piece of fine commercial property on stylish New Bond Street in Mayfair. Then came London’s retail renaissance, and New Bond Street-or New Bondstrasse, as it was derisively known in the trade-was overrun by the likes of Tiffany and Gucci and Versace and Mikimoto. Julian Isherwood and other dealers specializing in museum-quality Old Masters were driven into St. Jamesian exile-the Bond Street Diaspora, as Isherwood was fond of calling it. He eventually settled in a sagging Victorian warehouse in a quiet quadrangle known as Mason’s Yard, next to the London offices of a minor Greek shipping company and a pub that catered to pretty office girls who rode motor scooters.

Among the incestuous, backbiting villagers of St. James’s, Isherwood Fine Arts was considered rather good theater. Isherwood Fine Arts had drama and tension, comedy and tragedy, stunning highs and seemingly bottomless lows. This was, in large measure, a consequence of its owner’s personality. He was cursed with a near-fatal flaw for an art dealer: he liked to possess art more than to sell it. Each time a painting left the wall of his exquisite exposition room, Isherwood fell into a raging blue funk. As a result of this affliction he was now burdened by an apocalyptic inventory of what is affectionately known in the trade as dead stock-paintings for which no buyer would ever pay a fair price. Unsellable paintings. Burned, as they liked to say in Duke Street. Toast. If Isherwood had been asked to explain this seemingly inexplicable failure of business acumen, he might have raised the issue of his father, though he made a point of never-And I mean never, petal-talking about his father.

He was up now. Afloat. Flush with funds. A million pounds, to be precise, tucked nicely into his account at Barclays Bank, thanks to a Venetian painter named Francesco Vecellio and the morose-looking art restorer now making his way across the wet bricks of Mason’s Yard.

Isherwood pulled on a macintosh. His English scale and devoutly English wardrobe concealed the fact that he was not-at least not technically speaking-English at all. English by nationality and passport, yes, but German by birth, French by upbringing, and Jewish by religion. Few people knew that his last name was merely a phonetic perversion of its original. Fewer still knew that he’d done favors over the years for a certain bullet-headed gentleman from a certain clandestine agency based in Tel Aviv. Rudolf Heller was the name the gentleman used when calling on Isherwood at the gallery. It was a borrowed name, borrowed like the gentleman’s blue suit and gentleman’s manners. His real name was Ari Shamron.

“One makes choices in life, doesn’t one?” Shamron had said at the time of Isherwood’s recruitment. “One doesn’t betray one’s adopted country, one’s college, or one’s regiment, but one looks out for one’s flesh and blood, one’s tribe, lest another Austrian madman, or the Butcher of Baghdad, try to turn us all into soap again, eh, Julian?”

“Hear, hear, Herr Heller.”

“We won’t pay you a pound. Your name will never appear in our files. You’ll do favors for me from time to time. Very specific favors for a very special agent.”

“Super. Marvelous. Where do I sign up? What sort of favors? Nothing shady, I take it?”

“Say I need to send him to Prague. Or Oslo. Or Berlin, God forbid. I’d like you to find legitimate work for him there. A restoration. An authentication. A consultation. Something appropriate for the amount of time he’ll be staying.”

“Not a problem, Herr Heller. By the way, does this agent of yours have a name?”

The agent had many names, thought Isherwood now, watching the man make his way across the quadrangle. His real name was Gabriel Allon, and the nature of his secret work for Shamron was betrayed by subtle things he did now. The way he glanced over his shoulder as he slipped through the passageway from Duke Street. The way that, in spite of a steady rain, he made not one but two complete circuits of the old yard before approaching the gallery’s secure door and ringing Isherwood’s bell. Poor Gabriel. One of the three or four best in the world at what he does, but he can’t walk a straight line. And why not? After what happened to his wife and child in Vienna… no man would be the same after that.

He was unexpectedly average in height, and his smooth gait seemed to propel him effortlessly across Duke Street to Green’s Restaurant, where Isherwood had booked a table for lunch. As they sat down, Gabriel’s eyes flickered about the room like searchlights. They were almond-shaped, unnaturally green, and very quick. The cheekbones were broad and square, the lips dark, and the sharp-edged nose looked as though it had been carved from wood. It was a timeless face, thought Isherwood. It could be a face on the cover of a glossy men’s fashion magazine or a face from a dour Rembrandt portrait. It was also a face of many possible origins. It had been a superb professional asset.

Isherwood ordered stuffed sole and Sancerre, Gabriel black tea and a bowl of consommé. He reminded Isherwood of an Orthodox hermit who subsisted on rancid feta and concrete flatbread, only Gabriel lived in a pleasant cottage on a remote tidal creek in Cornwall instead of a monastery. Isherwood had never seen him eat a rich meal, had never seen him smile or admire an attractive pair of hips. He never lusted after material objects. He had only two toys, an old MG motorcar and a wooden ketch, both of which he had restored himself. He listened to his opera on a dreadful little portable CD player stained with paint and varnish. He spent money only on his supplies. He had more high-tech toys in his little Cornish studio than there were in the conservation department of the Tate.

How little Gabriel had changed in the twenty-five years since they had first met. A few more wrinkles around those watchful eyes, a few more pounds on his spare frame. He’d been little more than a boy that day, quiet as a church mouse. Even then, his hair was streaked with gray, the stain of a boy who’d done a man’s job. “Julian Isherwood, meet Gabriel,” Shamron had said. “Gabriel is a man of enormous talent, I assure you.”

Enormous talent, indeed, but there had been gaps in the young man’s provenance-like the missing three years between his graduation from the prestigious Betsal’el School of Art in Jerusalem and his apprenticeship in Venice with the master restorer Umberto Conti. “Gabriel spent time traveling in Europe,” Shamron had said curtly. That was the last time the subject of Gabriel’s European adventures was ever raised. Julian Isherwood didn’t talk about what had happened to his father, and Gabriel didn’t talk about the things he had done for Ari Shamron, alias Rudolf Heller, from approximately 1972 to 1975. Secretly, Isherwood referred to them as the Lost Years.

Isherwood reached into the breast pocket of his jacket and withdrew a check. “Your share from the sale of the Vecellio. One hundred thousand pounds.”

Gabriel scooped up the check and pocketed it with a smooth movement of his hand. He had magician’s hands and a magician’s sense of misdirection. The check was there, the check was gone.

“How much was your share?”

“I’ll tell you, but you must first promise me that you won’t divulge the figure to any of these vultures,” Isherwood said, sweeping his hand across the dining room of Green’s.

Gabriel said nothing, which Isherwood interpreted as a blood oath of everlasting silence.

“One million.”