"Imagine what you could achieve. Where others hesitate, you will act. Where others set boundaries, you will cross them, unhampered by any moral restraints or pangs of disquiet, any rules or ethics, with ice water in your veins and a heart of pure stone.

"What will you do with this power? That will depend upon what your desires are. Not all psychopaths are the same. And despite what the tabloid newspapers say, they're not all serial killers or ma.s.s murderers.

"Based on the law of averages, at least four people in this theatre match the description I've just given. Maybe you're sitting next to one of them. Maybe you're one yourself."

There are nervous smiles among the audience, but n.o.body looks sideways. They are listening.

"We are all different. Some of us are fuelled by ambition or a l.u.s.t for money or power. Some are lazy. Some are stupid. Some are violent. Some are cowards. Some, as I've explained, are psychopaths. Not monsters. Not madmen. They marry, raise families and create business empires, learning to fake sincerity and hide their secret.

"This concept of the successful psychopath is often forgotten or ignored by the medical profession. We study those on the fringes of society-the dropouts and low achievers, the ones who get caught who have neither the intellect nor the inclination to rule the world. Only in the last few years have we begun to investigate the psychopaths who hide successfully among us."

Glancing at my audience, I recognize one or two faces. I worked on a research project with Eric Knox, who is sitting next to Andrew Nelson, a friend from university, who once dated my sister Rebecca and broke her heart. Two rows back, I notice a woman who looks familiar. It takes me a few minutes to put a name to her face: Victoria Naparstek, Augie Shaw's psychiatrist.

"I'm going to end with a story," I tell them. "It's about an affable, charismatic man who grew up in a lower-middle-cla.s.s neighborhood of New York. Reclusive, stand-offish, slightly aloof, he married his childhood sweetheart and had two sons.

"He started a money management business, handling investments for friends and family. Success followed: a penthouse apartment in Manhattan, shares in two private jets; a yacht moored off the French Riviera. By his seventies he was managing billions of dollars for individuals and foundations, constantly signing up new clients including charities, public inst.i.tutions and investment firms.

"He shunned one-on-one meetings with most of his investors, but that only increased his allure. He also avoided the Manhattan c.o.c.ktail circuit, fostering his reputation as a financial mastermind blessed with the Midas touch-the sage of Wall Street. Does anybody know who I'm talking about?"

"Bernie Madoff," says a voice from the darkness.

"A cla.s.sic psychopath; a charlatan of epic proportions, a greedy manipulator so hungry to acc.u.mulate wealth that he destroyed the lives of thousands of people and didn't lose a moment's sleep.

"He had education, money, opportunity, a magnificent IQ and absolutely no vestige of conscience. Never blinking, never fearing exposure, he engineered the largest Ponzi scheme in history, convinced that he was above the law and that his victims were stupid, unworthy and contemptible.

"Madoff isn't a one-off. There are many like him out there. They choose business, politics, law, science, banking and international relations; pursuing their chosen career with a ruthless, single-minded efficiency, unenc.u.mbered by moral uncertainty or guilt, without regard for anyone else.

"They stab colleagues in the back, undermine rivals, ruin enemies, fabricate evidence, shred the truth, lie, cheat, steal and ride roughshod over everyone who stands in their way. Sometimes they marry for money. Divorce for money. Embezzle funds. Bankrupt charities. Start wars. Invade countries. Crush the powerless. Corrupt the innocent. And always with the exquisite freedom of knowing they will sleep peacefully at night.

"These are not the psychopaths who you and I treat in our consulting rooms. Maybe that's a good thing. Maybe it's not an issue of treating them. They're not broken-they just are. It's a personality trait, not a personality disorder."

A hand is raised; a young man, perhaps a postgraduate student. "Aren't we obliged to treat them?"

"Why?"

"They need our help."

"What if all we're doing is giving them the skills to fake sincerity and become better psychopaths?"

My inquisitor isn't satisfied. "Surely you're exaggerating the problem?"

I stop my left arm from trembling. "I read a newspaper story this morning that anorexia has reached epidemic proportions in this country. There are four times as many psychopaths in this country as people with eating disorders. Does that make it an epidemic or an exaggeration?"

I take a handful of further questions, most of them focused on the empirical data. I warn them not to get too caught up in the statistics. They're important to scientists and students, but less so for clinicians. Human behavior can't be broken down into bell curves and graphs.

"On July 24, 2000, the Concorde was the safest aircraft in the world. A day later-according to the statistics-it was the least safe airline in the world. Beware the data."

The lecture is over. Seats slowly empty. n.o.body approaches me. Dr. Naparstek hasn't renewed our acquaintance, which creates a pang of regret. She's a good-looking woman, attractive without trying. Late-thirties. Slim. Stylish. Out of my league.

Am I even playing in a league?

Julianne put me on a free transfer list three years ago and n.o.body has made me a serious offer-not even a guest appearance in a friendly.

Outside in the foyer everyone is talking about the weather. A voice makes me stop.

"Augie Shaw didn't kill those people."

Victoria Naparstek is standing beside the doors. She's wearing a gray woolen sweater dress, black nylons and knee-length leather boots.

"I thought you'd be honest. Fearless. You let Stephen railroad you."

"Stephen?"

"DCI Drury."

They're on first name terms.

"You told him what he wanted to hear."

"I gave him my opinion."

She steps forward, studying me. Her eyes seem to change color as she moves. "They're applying to keep Augie Shaw in custody for another forty-eight hours."

"Which has nothing to do with me."

"He didn't kill those people."

"He was there."

"He has no history of violence. He doesn't cope well with confined s.p.a.ces. The last time they locked him up-"

"The last time?"

"It was a mistake. He was exonerated."

Her hair is cut shorter than I remember. Instead of long rope-thick tresses, she has a chin-skimming bob that sweeps over her cheekbones and ends at the nape of her neck.

"I'm frightened that he'll harm himself."

"Tell Drury."

"He won't listen to me."

She glances at my left hand. My thumb and forefinger are brushing together in a pill-rolling motion.

"Do I make you nervous?" she asks.

"I have Parkinson's."

Her mouth forms a lipstick circle. She tries to apologize.

"You weren't to know," I say.

"I'm doing everything wrong today. Can we start again? I could buy you lunch."

"Or we could go halves."

A smile this time... dimples.

"I know just the place," she says, marching ahead of me. I check out her figure, forever hopeful. She takes me to the Head of the River, a pub alongside Folly Bridge. Pushing open the heavy door, she takes my coat and hangs it on a hook. Then she chooses a table away from the fire. Orders mineral water. Asks about wine.

"I don't drink."

"Your medication."

"Yes."

"What are you on?"

"Levodopa for the symptoms, carbidopa for the nausea, Prozac to stop me being depressed about having a major degenerative illness."

"How bad does it get?"

"This is a good day..."

We sit a bit, staring at the table as though fascinated by each other's cutlery.

Victoria Naparstek is a little different from what I remember. Her clothes are less feminine, more practical. A string of pearls makes her look older. Maybe she grew tired of being objectified, which would make her unusual among women.

"Are you here alone?" she asks.

"With my eldest daughter Charlie... she's out somewhere spending my money."

"You're married?"

"Separated. Three years. Two girls. Fifteen and seven. They live with their mother, but I see them quite a bit; less now that I'm in London."

"Mmm."

"What?"

"It's interesting."

"What is?"

"I asked a simple question and you gave me your entire life story-everything except your favorite color."

"Blue."

"Sorry?"

"My favorite color is blue."

I look at the menu. Victoria orders the soup. I do the same. Terrible choice. My left arm trembles.

I change the subject and ask about her practice. She lives in west London, but travels to Oxford two days a week, working mainly for the NHS.

"How did you come to treat Augie Shaw?"

"He turned up at a police station two years ago and confessed to raping a woman, but it was a false complaint."

"She wouldn't press charges?"

"She'd never seen him before. Augie fantasized about raping her. I think he genuinely believed that he'd done it. He was mortified. Shocked. Angry at himself."

"You stopped him in time."

"He stopped himself." She runs her finger around the edge of her gla.s.s. "Augie started having problems in his late teens. Auditory hallucinations. Blackouts. Disorganized thinking. Chronic headaches. Insomnia. He claimed to get contrary messages whenever he had to make an important decision."

"Messages?"

"From his twin brother."

"Drury said he doesn't have a brother."

"His twin died at birth but Augie believes he's still corded with his brother's soul. He says it's like his twin is trapped inside him and won't leave."

"Paranoid schizophrenia."

"Delusional ideas-some grandiose, others paranoid."

"Medication?"

"Anti-psychotics: olanzapine fifteen milligrams and sleeping tablets. During our sessions, I tried to get Augie to mentally cut the cord, but he's resistant. He thinks half his personality will disappear if he loses contact with his brother."

"You mentioned claustrophobia?"

"Augie's father used to lock him in a cupboard when he was a boy. He still suffers nightmares. He hates confined s.p.a.ces. He also believes that inside air is poisonous and that's why his brother died in the womb."

"You said he had no history of aggression."

"He doesn't."

"He fantasized about raping a woman."

"He was delusional."

"He was sacked by the Heymans for going through their daughter's underwear."