Nelson Aldrich Jr., the son, grandson and great-grandson of millionaires, did not set out to live his life as a sociological experiment. Yet though he was raised with many of the trappings of great wealth—the schools, the clubs and the summer homes—he was conspicuously lacking in cash. It was this singular deprivation that led to his discovery that it was less "the reality of unearned wealth" that guaranteed one's position in the world of "old money" than "imagination and pure training." In 1926, F. Scott Fitzgerald pronounced the rich "different from you and me." Now comes Aldrich to explain those differences in his new book, Old Money, the Mythology of America's Upper Class.

Before getting it all down, though, Aldrich, 53, had to exorcise some of the demons of his own privileged upbringing. His parents divorced when he was 3, and by the age of 8 little Nelson had been turned over more or less full-time to the "silver-spoon curriculum": the Fay School in Southboro, Mass., St. Paul's and then Harvard, where he joined that most high society, the Porcellian Club. By the time Aldrich discovered that he would inherit almost no money of his own—his father, an architect, lost a small fortune in business, and his mother, who married four times, left most of hers to the housekeeper—he was so steeped in trust-fund culture that he found himself indifferent to earning a living.

"Just as the nouveau riche will always feel poor, so the nouveau pauvre are always convinced they really are rich," says Aldrich, who concedes that his own résumé "reads like the yellow sheet of a repeat offender." After a sojourn in France working for the Paris Review, Aldrich taught school in Harlem, reported for the Boston Globe, edited at Harper's, produced a TV program and worked as a lobbyist. None of these jobs lasted very long. Schooled in "the airy inconsequentially of working," Aldrich says, he would inevitably alienate his employers.

Like many children of old money, Aldrich has also been given to romantic, irresponsible gestures—afflicted with the same "moral carelessness," he says, that is evident whenever a young heir dives into drugs, promiscuity or dangerous sports to make a gossamer life seem more real. A heady affair with a married woman in Paris produced a love child—now 26 and living in London. Five years later, settled in New York, Aldrich wed Anna Lou Humes, a young divorcée on her own with four daughters. It seemed a "gallant, dashing thing to do," he says, "rescuing the damsel in distress." But in the end, it was he who needed rescuing, thanks to his other great romance—with the bottle. In the late '70s, when Aldrich was drinking heavily, Anna Lou—who became a bank officer—was often the principal breadwinner for the family. Though she and Nelson have been separated since 1981, Old Money is dedicated to Anna Lou because, says Aldrich—sober now for five years—"she always propped up my morale." Learning of the dedication a few months before publication left Anna Lou "shaken and curious," she says. "But now I'm very pleased. It's a wonderful book."

Many critics agree. The Atlantic Monthly calls Old Money "the best nonfiction book about the American upper class written by one of its members since Henry Adams' Education." Blending autobiography and social history, Aldrich—who's related to the Rockefellers—discusses the special facts of life cushioned by money that is, by and large, "just there"—long separated from any nastiness involved in its acquisition. (Aldrich's great-grandfather, the first Nelson, a Rhode Island grocer, entered the Senate in 1881 worth $50,000 and left 30 years later worth $12 million, thanks to the kindness of grateful monopolists.) One such fact, familiar to any child ever to hunch down in the family limousine in an agony of shame and pride, is the humiliating public perception that "inheritors of old money are lightweights"—sissies, wimps, dilettantes and degenerates. To counter that, says Aldrich, old money sets its young a series of personal "ordeals": boarding school, the high seas, war.

Aldrich also explains why polo is the perfect old-money game. It's not just because the horses and equipment cost a fortune, but rather because the sport is almost impossible to master. "To play it well, one has to have always—past perfectly—played it," he says. "The entrepreneur cannot learn it without looking ridiculous. All he or she can do is buy the clothes associated with it." And so it goes for all efforts to reduce old money to a set of marketable products—as if there were, Aldrich writes, "nonchalance sold along with naturally-tailored suits, magnanimity arriving in the mail with every L.L. Bean catalog or a sense of fair play included in the warranty of each Volvo station wagon." Perhaps it's just as well these carefully inculcated old money attitudes cannot be readily retailed, since they often go hand in hand, Aldrich notes, with others, such as racial prejudice and stultifying habit.

Yet Aldrich neither condemns nor defends his class. Indeed, his cousin Dr. Graham Blaine charges Aldrich with "hedging his bets...wanting to be both an on insider and an outsider." In a sense, though, Aldrich was always that—the poor boy at the ball. And since he has already suffered some of the pitfalls of having been born into money, he wouldn't mind having a bit. "It's nice to be famous," says Aldrich with a laugh, delighted with the critical reception to his book. "But how do I get rich?"