Kroll in his office in New York City. Photograph by Platon

When Jules Kroll was a kid, in Bayside, Queens, his father had a printing business—“a miserable little company,” according to Kroll. It was the nineteen-fifties, and what Kroll mainly remembers from watching his old man go over the books at the kitchen table on Sundays are the humiliations that his father suffered at the hands of purchasing agents, many of whom required “gifts”—kickbacks—before they would give him work. “It was pretty dispiriting,” he says. “It made me pretty angry.” Later, when his father fell ill, Kroll, by then a young Assistant District Attorney in Manhattan, had to come home and run the business. A three-month leave of absence turned into three claustrophobic years. But the experience gave Kroll an idea. He made the rounds of companies that had a lot of printing done. He could save them money, he said. He knew where the graft was in their printing jobs—the bribes and the waste and overpayments. He wasn’t asking for a fee, just a percentage of whatever he saved them. The parent company of Marvel Comics was the first to agree, and Kroll was soon saving the company so much that it tore up the percentage deal, which might have made Kroll rich, and put him on a retainer.

Kroll told this story, probably not for the first time, to a crowd of students and faculty at Cornell last fall. “Spider-Man, the Hulk—I really owe my business to those superheroes,” he said. Kroll’s business, launched in 1972 as J. Kroll Associates, eventually became Kroll, Inc., the world’s preëminent detective agency, with three thousand employees, countless subcontractors, and offices in sixty cities in more than thirty-five countries.

According to the history professor who introduced Kroll that day, Kroll, Inc., specializes in “pursuing crime, particularly financial crime, across international borders.” And so Kroll told stories about recovering the wealth plundered by dictators, among them Ferdinand Marcos, Saddam Hussein, and Jean-Claude (Baby Doc) Duvalier. Baby Doc, Kroll said, was “not the sharpest nail in the box.” He had looted the Haitian treasury by writing big checks. “Apartment in Trump Tower?” Kroll made a show of laborious penmanship. “ ‘Trump . . . Tower.’ Even we could figure that one out.”

Kroll is sixty-eight, tall, bald, and solidly built—he played rugby at Cornell, and was the starting catcher on the freshman baseball team. He moved stiffly, like an old athlete, as he paced the well of the lecture hall, and digressed freely, offering an account of how he had taken his future wife, Lynn, on a study date here at Cornell. (“You still have study dates?” Pause. “No.”) There was a large, alarming gash on the right side of his skull—it looked like a fresh machete wound. It was an incision from skin-cancer surgery, as Kroll eventually explained, adding that there was a lesson to be drawn from that: wear a hat. Kroll’s stories were nearly all morality tales. Abuses of trust are chronic and toxic, but they are there to be exposed. “The world is not becoming a more corrupt place,” he told the students. “In fact, it’s getting better. The issue of integrity is alive everywhere.” His role, his company’s role, was—Lynn hated this image, he said—“to help keep the fish tank clean.”

The first question, from a Nigerian student, was more in the nature of a plea. “In my country, you cannot imagine the corruption,” the young man said. “It is everywhere you look, and you can be killed for saying anything. Please, please come to Nigeria. We need you.”

“O.K.,” Kroll said, one hand outstretched as if to steady the young man. “O.K.” Kroll’s gaze—he has big, slightly bulging pale eyes—did not leave the Nigerian’s. “We are there. We’ve been to Nigeria about ten times in the past year or two. People exist there who want to turn things around. It’s a very tough environment. But we are there.” He asked the young man to write down his contact information.

A student from Germany asked how Kroll had the authority to conduct investigations. Wasn’t that role reserved for the police?

“No” was the short answer. Kroll needed a license to operate, that was all. Kroll then told a story about an American telecommunications company that was being extorted by Turkish hackers in Germany. The F.B.I. was not ready to get involved, so the company brought in Kroll. Kroll sent an operative into the hackers’ midst, quickly gathering enough evidence to interest the F.B.I. “This is how I make my living,” Kroll said. “The F.B.I. is busy.”

Actually, that’s not how Kroll has made his living, or, at least, not most of it. Breaking up extortion rings, nailing dictators—that’s the Marvel Comics version of Jules Kroll’s career. Kroll really made his living, and his name, on Wall Street. He owed his success not to Spider-Man but to Goldman Sachs and Skadden Arps and a long list of corporations, law firms, investment banks, management consultants, hedge funds, and brokerage houses. Kroll likes to say, “Sunlight is a wonderful antiseptic.” But he and his company have been more highly valued for keeping things in the dark than for the occasional, client-approved exposé. They are the keepers of innumerable embarrassing, probably career-destroying, possibly corporation-destroying secrets. Jules Kroll may pose, credibly, as a crusader for truth and justice, but his life has been more interesting than that.

Kroll is widely credited with having created an industry where there was none. Call it corporate intelligence. There were, of course, plenty of detective agencies and security companies around when he started, but successful private investigators in the United States—Pinkerton, Wackenhut—have tended to expand into guard and alarm operations. Kroll took his business in another direction: upward, into finance and strategic planning. He offered an ever-widening range of services—forensic accounting, crisis management, competitor analysis—tooled for a globalized business world, in which industrial espionage, counterfeiting, computer fraud, identity fraud, and sophisticated financial crimes have flourished.

“He was legitimatizing private-detective work at a different level,” Joe Rosetti, who was the vice-chairman of Kroll until 2001, said. Rosetti was the security director at I.B.M. when Kroll recruited him, in the early eighties.

In 2004, Kroll sold his company to Marsh & McLennan, an insurance conglomerate, for nearly two billion dollars in cash. Kroll, already a wealthy man, pocketed around a hundred and seventeen million dollars (his ownership stake, once a hundred per cent, was diluted after he took the company public, in 1997), and he stayed on to run Kroll, Inc., as a Marsh subsidiary. He retired in July, 2008. Constrained by a one-year non-compete agreement with Marsh from conducting any Kroll-type business, but now unconstrained by the client interest and discretion that had always restricted his role in public debates, Kroll began to speak in lectures and interviews about failures of corporate governance and the deep flaws of standard investment models. He knows an unusual amount about what laid the financial industry low last year. For traumatized investors betrayed by the credit-risk rating agencies, what is needed, he says, is “a whole new risk model.”

“Risk mitigation” is one of Kroll’s preferred descriptions of his line of work. Like other catchphrases that he has employed through the years—“professional services,” “management consulting”—it helps rub off the patina of seediness attached to the term “private investigator,” something that has been the bane of his branding efforts since the day he started. And in the integrity business—yet another way he describes his field—brand is everything.