If there's a lesson in money-manager Bernard Madoff's bilking his clients of US$65 billion in the biggest one-man fraud of all time, it's that you should never entrust your life savings to a psychopath.

The trick, however, is to spot the psychopath under the sheep's clothing; the greedy fiend behind the philanthropist's smile; the money-sucking vampire inside the hail-fellow-well-met, the moral rot at the heart of the charm.

On lists of the symptoms of psychopathy - which should drive you as far away as you can possibly get from anyone who exhibits them - "superficial charm" usually ranks ahead even of "grandiose sense of self-worth," "pathological lying," and "cunning/manipulative."

"Superficial" suggests the charm is easy to see through, and therefore doesn't work, but one reason why psychopaths manage to ruin or destroy so many people lies in their ability to be truly charming. American psychiatrist Hervey Cleckley once wrote that the true psychopath conceals behind "a perfect mimicry of normal emotion, fine intelligence and social responsibility, a grossly disabled and irresponsible personality."

"Madoff seemed to humanize the cold, frequently anonymous business of investing by giving it an avuncular face," New York journalist Daphne Merkin writes. "By all accounts, he was the quintessential nice guy. And no small thing: he looked trustworthy. He has the sort of pleasant mien that makes you think he has your best interests at heart."

But in photos, after he pleaded guilty to all 11 charges that arose from his stupendous thievery, Madoff's mien has lost its pleasantness. He's wearing handcuffs as guards lead him out of a courtroom and, if I may borrow from Shakespeare, his eyes look "as cold as a dead man's nose."

"Mr. Madoff was expressionless throughout," Joe Nocera reported in the New York Times. "When he read a statement recounting his crimes and expressing 'remorse,' he sounded like a man reading a speech he hadn't bothered to rehearse."

Outside the courtroom, Cynthia Friedman told the BBC that, owing to the machinations of Madoff, she and her husband had lost US$3 million. Madoff was "a horrible man . . . just an awful man . . . evil incarnate." His apology fooled neither her nor the others who clapped when court officials handcuffed him.

"He has no remorse," she said.

Another Madoff investor added, "I think the only thing he feels is regret that he got caught."

Too late for their own good, these people fingered the central and horrible defect of the classic psychopath: his inability ever to feel even the faintest twinge of empathy for his victims, or remorse for what he did to them. Some psychologists believe this "severe emotional detachment" is incurable. (I use male pronouns because men psychopaths, of whom there may well be two million in North America, far outnumber psychopathic women.)

"Psychopath" makes one think of serial killers like Jack the Ripper, the Boston Strangler, Ted Bundy and John Wayne Gacy, but the crimes of most psychopaths are less bloody and hideous than theirs.

Your run-of-the-mill pyscho appears harmless to those who don't know him well while he imposes pain of one kind or another on those who do. Like Madoff, he often thrives in the world of business and finance.

He may well be egocentric, ruthless, manipulative, audacious, good at selling himself, and restrained by neither a social conscience or the willingness to accept responsibility for the damage he causes. He hates boredom and loves the challenge of adapting to competitive environments.

Isn't he just the sort of fellow greedy shareholders might want as a chief executive officer?

Dr. Robert H. Hare, an American researcher who knows as much about psychopaths as anyone, says we should make no distinction between a Bundy, who murdered more than 30 young women, and the perpetrators of the gigantic accounting fraud at the Enron Corporation.

"Can you say Ted Bundy caused more disaster than the guys at Enron?" Hare asks in The New Yorker. "How many destroyed lives and suicides followed as a result of so many people losing their savings?"

I have a question of my own.

In Washington and on Wall Street, how many rich, powerful psychopaths did it take not to change a light bulb but to plunge the entire world into the worst calamitous economic crisis in eight decades?