Though access to the British royal family is not supposed to be for sale, Sarah Ferguson, the Duchess of York, recently fell prey to a "businessman" who paid her $40,000 to arrange a meeting with her ex-husband, Prince Andrew. (Watch a CBS report about Sarah Ferguson's meeting.) The persuasive businessman was, in fact, Mazher Mahmood, the undercover journalist known as "the Fake Sheikh" who's hoodwinked dozens of celebrities and claims to have brought 234 criminals to justice, inspiring Time to dub him "one name in British journalism that inspires fear and loathing in just about equal measure." Here's a concise guide to the secretive undercover hack:

1. First things first. What happened with Fergie?
Mahmood, a journalist for the tabloid News of the World posed as an "international tycoon" seeking an audience with Prince Andrew, whom The Guardian says "acts as a quasi-official British trade envoy promoting deals for U.K. firms around the world." His ex-wife accepted a $40,000 cash down payment, and sought 500,000 pounds more as payment for arranging a meeting, saying on tape: "Look after me and he'll look after you."

2. How did Mahmood get such privileged access?
He used his standard modus operandi: Other News of the World investigators "infiltrated [the duchess'] close circle of associates," and arranged a meeting with Mahmood.

3. Why is he called the Fake Sheikh?
British tabloid The Sunday People gave Mahmood the nickname in 1984 after he exposed a vice ring dressed as an Arab sheikh. In his "stings," Mahmood — born to Pakistani immigrants — often poses as a wealthy Arab or a businessman named "Sam Fernando."

4. Who else has the journalist duped?
Among his high-profile targets are former England soccer coach Sven-Goran Eriksson and former world champion boxer Joe Calzaghe. He has also exposed British politicians, sports stars, and celebrities for drug-dealing, corruption, and adultery.

5. Was Fergie the first royal he's targeted?
No. Prince Edward's wife, Sophie, was recorded in conversation with Mahmood in 2001 making insulting comments about the royal family, Tony Blair, and his wife.

6. Are famous people his only targets?
No. He also exposes pedophiles, human-traffickers, terrorists, and other criminals. In 2002, he famously revealed a 5 million pound plot to kidnap David Beckham's wife, Victoria, infiltrating the kidnapping ring and worked with Scotland Yard to bring them to justice. (The case collapsed, however, because Mahmood's informant had been paid for his story.)

7. Are his tactics legal?
Though they are regularly criticized, he's never been arrested. "Mahmood's methods debase journalism," wrote former tabloid editor Roy Greenslade. "They often amount to entrapment and, on occasion, appear to involve the use of agents provocateurs. People have been encouraged to commit crimes they would not otherwise have conceived."

8. Does he always get things right?
Not always. He was widely criticized for a 2006 exposé of three supposed terrorists' attempts to buy material for a "dirty bomb," which was comprehensively debunked in the British courts. Following the trial, after which all three of the accused walked free, defense lawyers called Mahmood "dangerously deceitful, ruthless, exploitative, and corrupt."

9. What else do we know about him?
Not much. "Mahmood keeps his identity as mysterious as possible," says Nick Assinder in Time. "No one is entirely sure of his background, or if Mazher Mahmood is even his real name." The journalist claims to have received many death threats, does not appear in public, and has never allowed his face to appear in any of his stories.

10. How much would I have to pay to meet him?
He may indicate a price range in his memoir, Confessions of a Fake Sheik: The King of Sting Reveals All.