There are no beggars, no factory workers, no coal miners, hospital nurses, outsourced office hands or middle school teachers who figure prominently in Plutocrats (Penguin Press, 336 pages, $27.95), Chrystia Freeland’s new book on rising income disparity. (Call-center workers at startup whiz Tony Hsieh’s Zappos do make a cameo.) That’s by design. It’s Ms. Freeland’s stated intent to examine the widening gap between the mega-rich and the rest of us through the lives and careers of the men—yes, men—at the top. (The book’s full, ominous title is Plutocrats: The Rise of the New Global Super Rich and the Fall of Everyone Else.) That means, as her discussion of the distaste affluent Americans have for the word “rich” suggests, a study of the plutocrats on their own terms, and not, say, according to the 99/1 rhetoric posited by Occupy Wall Street.

And so the book is populated by financial, technological and emerging-market entrepreneurs peering down from their mountaintops, as well as the closest cousins of the fortunate few: the elite artists, artisans and thinkers who cater to, study or simply swim in the slipstream of the extremely rich.

The operative word is extremely. Ms. Freeland, global editor at large for Reuters, takes readers to the 60th birthday party of private equity titan Stephen Schwarzman, at which Rod Stewart was reportedly paid $1 million to perform; to a lunch over Long Island-sourced striped bass with 20 bigwig investors at George Soros’s Southampton estate; and to visits with assorted billionaires, including LinkedIn founder Reid Hoffman, Russian oligarchs Mikhail Fridman and Viktor Vekselberg, and the son of Lakshmi Mittal, the richest man in India.

Carlos Slim, not just the wealthiest man in the world, Ms. Freeland tells us, but by one measure the wealthiest man in the history of the world, makes numerous appearances. Michael Bloomberg and Warren Buffett show up, naturally, as does Bo Xilai, the Chinese elite whose fortunes reversed when his wife was implicated in the murder of a British businessman.

It sounds titillating, but it isn’t. That’s also by design. Plutocrats isn’t a book about the lifestyles of the fabulously wealthy, but rather the global trends the book’s titular class surfed to success. Ms. Freeland isn’t interested here in the “original sins” that allowed men like Mr. Vekselberg to seize control of the Russian economy in the days of privatization (she told some of those stories in a previous book, Sale of the Century) but in locating the plutocrats’ winning instincts in economic, political and cultural contexts.

The result is something resembling a cocktail party at Davos or the Aspen Institute Ideas Festival or any of the other stops on the circuit of the mega-rich. The guests are long on intelligence, determination and self-confidence. The affect, as anyone who’s ever watched a TED Talk might surmise, is empirical and dry.

Plutocrats grew out of an article Ms. Freeland published in The Atlantic in January 2011, which postulated the rise of a new global elite and rested on two ideas that at the time I found thrilling. First, that a French banker working in Hong Kong, a Russian mogul decamped to London and an American tech entrepreneur in Silicon Valley have more in common with each other than any has with his own countrymen. Second, when masters of the universe identify along class lines rather than nationality, we’re one step closer to the kind of global egalitarianism that Karl Marx might have idealized. A factory closes in the Rust Belt, taking a bite out of the American middle class; a factory opens in Guangzhou, buoying Chinese standards of living. Maybe we shouldn’t be so quick to say that’s a bad thing.

Plutocrats doesn’t deliver any such strikes of lightning, but it’s rife with impressive analysis. In a chapter on the so-called superstar effect—“the tendency of both technological change and globalization to create winner-take-all economic tournaments”—Ms. Freeland glides from the writings of Soviet intellectuals, MIT and Princeton economists and the apostle Matthew to the careers of 18th century diva Elizabeth Billington, Lady Gaga, white-shoe lawyer David Boies, Yves St. Laurent, DreamWorks CEO Jeffrey Katzenberg and Albert Einstein.

The phenomena she describes are often self-apparent. Mario Batali maximizes earnings by selling lunch to Wall Street and cookbooks to everyone else. File-sharing extended pop stars’ reach, but undercut wealth for all but the select few who can use their massive popularity to fuel concert tours. These are not surprising concepts, but the thoroughness with which Ms. Freeland surrounds the ideas is satisfying.

The superstars, of course, are a side order. What we really want to know about is the billionaires who seem to remake the world with every new venture, a group that Ms. Freeland sorts into two overlapping chapters. By and large, she says, the plutocrats seized their fortunes by perceiving opportunities created by revolutionary change. But like the 19th century robber barons, they’ve also been enriched by the reallocation of public resources—rent-seeking, in economic parlance—and sought to influence government policy in service of their bulging bank accounts.