This fear led me to the Pavillion Agency, which specializes in finding domestic workers for New York City’s wealthy. Pavillion introduced me to Muneton, 49, who grew up in “a very poor family” in São Paulo. In 1990, she befriended a young American woman who had relocated to Brazil. When Muneton invited her to her family’s home, the woman saw her natural ease with children and suggested that she move to America and become a nanny. Within a few months, Muneton was caring for the children of a rich family in South Carolina for only $100 a week.

When Muneton started working through Pavillion in 2002, however, she increased her salary to $85,000 a year. As she gathered sterling recommendations, she began increasing her pay. Eventually she worked for some of the country’s wealthiest people, whom she accompanied on private jets to many of the world’s most exclusive resorts. Today, she says, “there are no more poor people in my family.” Muneton bought a nice house for her mother, a condo for her sister and a taxi cab each for two of her brothers. She also owns a beach house in Brazil, a penthouse in Miami and two properties (a six-unit building and a duplex) in Los Angeles.

How does a nanny earn more than the average pediatrician? The simple answer is hard work — plus a strange seller’s market that follows a couple of quirky economic principles. A typical high-priced nanny effectively signs her (and they are almost always women) life over to the family she works for. According to Cliff Greenhouse, Pavillion’s president, that kind of commitment is essentially built into the price. Many clients are paying for the privilege of not having to worry about their child’s care, which means never worrying if their nanny has plans. Which, of course, she can’t, pretty much ever.

And, alas, it seems that there just aren’t enough “good” nannies, always on call, to go around. Especially since a wealthy family’s demands can be pretty specific. According to Pavillion’s vice president, Seth Norman Greenberg, a nanny increases her market value if she speaks fluent French (or, increasingly, Mandarin); can cook a four-course meal (and, occasionally, macrobiotic dishes); and ride, wash and groom a horse. Greenberg has also known families to prize nannies who can steer a 32-foot boat, help manage an art collection or, in one case, drive a Zamboni to clean a private ice rink.

And then there’s social climbing. “A lot of families, especially new money, are really concerned about their children getting close to other very affluent children,” Greenhouse says. “How do they do that? They find a superstar nanny who already has lots of contacts, lots of other nanny friends who work with other high profile families.” There are the intangibles too. “I’m working with a phenomenal Caribbean nanny right now,” Greenhouse says. “She is drop-dead beautiful. Her presentation is such that you’re proud to have her by your children’s side at the most high-profile events.”