When Ryan D'Agostino travels -- to a wedding, on a vacation -- he usually winds up walking with his wife through the ritzy part of town.

"Whenever we wander into a neighborhood of bigger, more beautiful homes on sprawling lots, invariably one of us asks, 'Why don't we get to live there? And who does?' "

D'Agostino, an editor at Esquire magazine, attempts to answer those questions in his new book, "Rich Like Them." He devised a formula using median incomes, home values and disposable incomes to come up with a list of the nation's 100 wealthiest ZIP codes. Then, notebook in hand, he went to 19 towns in 11 states and knocked on 500 doors.

Half of the people weren't home. Fifty housekeepers shrugged him off, while 150 others declined and rechecked their security systems. But 50 people -- from Atherton, Calif., to Westport, Conn. -- invited him into their marble foyers.

His hope was to "gather enough insight and guidance to help me -- and you, and anyone else who reads this -- understand how to get rich; rich like them."

I was fully prepared to not give a hoot about the snobs foolish and pompous enough to let this writer into their mansions. But D'Agostino never takes himself too seriously and I found myself intrigued, and even inspired, by some of the characters he introduces.

Lake Forest, Ill. -- ZIP code No. 30 -- is the closest he gets to Minnesota. That's where we meet my favorite rich guy in the book, Frank Heurich, in his manse on Lake Michigan. He made his money concocting a shrimp-peeling machine. Go figure.

Not all of the rich folk emerged from D'Agostino's cold-knocking. The shrimp-peeler, for example, came via a tip from a college friend. D'Agostino also parlayed a phone call to the mayor of Atherton, Calif., the No. 1-ranked ZIP code, to gain access to that city's upper crust. And happy hour at the El Chorro bar in Paradise Valley, Ariz., led to Harland Young. He lost his shirt on a take-home-pizza idea, but soared when he turned his cabinetmaking hobby into his livelihood.

Perhaps the best snippet in the book features the independent rock band Dispatch, which happens to be made up of some of D'Agostino's college pals and for whom he once served as chief roadie.

The book drags when D'Agostino sprinkles in experts and practical get-rich gobbledygook, such as: "Squeezing a great idea out of your brain begins with having the right outlook on the moments that make up your life."

And since the book was written in 2006 and we've endured a little catastrophic financial collapse since it went to the printer, readers can't help but wonder if some of the rich people we meet aren't now in foreclosure.

But the book works once those rich people open their doors. From an early Dell computer woman in Austin, Texas, to the eye doctor outside Cleveland, from wily real estate investors in Las Vegas to art dealers in California, D'Agostino's door-knocking shtick gives us some insights on wealth, risk and decision-making.

Staff writer Curt Brown is the author of "So Terrible a Storm: A Tale of Fury on Lake Superior."