In their quest for social change, givers like Arnold are reluctant to support “causes”; they want to “solve problems—big ones,” as Callahan puts it. But, in Arnold’s case, lessons had to be learned along the way. His early forays into philanthropy, including an effort to reform public pensions, were scorned, with critics noting that Enron’s collapse had resulted in the loss of billions of dollars in pension funds.

Moskovitz and Tuna weren’t keen to embrace traditional development organizations, which they are inclined to view as lethargic and bureaucratic. For them, grant making is akin to venture-capital investing: they want to act decisively and disrupt traditional models and structures. They have contributed $32 million to a group called Give Directly, which is not interested in vaccinating children, digging wells, building toilets, and creating schools. Rather, it gives cash handouts to the poor, who are free to spend the money as they wish. Callahan is skeptical of the ideology guiding Moskovitz and Tuna—who favor Silicon Valley mantras such as “empower individuals over institutions”—but he knows they are too influential to ignore. The couple will give away hundreds of millions of dollars every year. They are not yet thirty-five years old.

There are growing concerns about the influence and reach of the superwealthy: “Philanthropy is becoming a much stronger power center,” Callahan says, “and, in some areas, is set to surpass government in its ability to shape society’s agenda.” The state has retreated; the givers have advanced.

in many U.S. cities, elected officials are overwhelmed by debt obligations, and as a result have precious little money to spend on parks, museums, and other public services. The givers have no such constraints. In Boston, the Barr Foundation has done much to shape the city’s arts, culture, and political milieu. In Houston, Richard Kinder is helping to forge a massive network of urban trails. In Detroit, the Kresge Foundation is contributing funds for a new light-rail system. In New York, the Leon Levy Foundation has helped to revitalize a pair of Brooklyn landmarks, the Brooklyn Public Library and the Brooklyn Botanic Garden. These are worthy endeavors, but Callahan is right to express concern about a fundamental shift of power from a “hollowed-out public sector” to elite private givers who are not fully accountable and operate in dark corners.

In 2008 Stephen A. Schwarzman, another cofounder of Blackstone, gave $100 million to the New York Public Library at a moment when the Library was secretly undertaking a dubious real estate and construction scheme. For nearly a decade, the NYPL refused to reveal how Schwarzman’s money was being utilized. Only in recent months did the Library account for the gift’s use: the $100 million formed part of the endowment and will soon be used for new renovation projects.

Under an initiative backed by Broad and like-minded funders, L.A. could add hundreds of new charter schools in a decade. Broad is quick to refute allegations that he is overreaching: “I think everyone is getting heard,” he informed Callahan. “We’re getting heard, the philanthropists. The unions and administrators are getting heard. Overall, we’re creating debate.”

That may be so, but increasingly the debate is among people who already agree. The Givers makes a persuasive case that the superwealthy are expanding their influence at a moment when many Americans are bolting from civic and political life. The author, drawing on the scholarship of Theda Skocpol, evokes an earlier era when mass-membership organizations such as trade unions flourished, giving ordinary citizens a certain degree of influence vis-à-vis elite power structures. These days, he writes, “We’re fast moving toward a future where private funders, not elected officials and the citizens they answer to, choreograph more of public life.”

Of the top eighty American foundations, only twenty-six post detailed information about their current grant making on public databases. The Susan Thompson Buffett Foundation, endowed by Warren’s wealth, “has no real website and the information available on its grant making through tax returns is always a few years out of date,” Callahan notes.

The Givers is alive to these and other contradictions in the philanthropic sector and poses thorny questions for elected officials and nonprofit leaders: why is a check to a right-wing think tank tax-deductible but a check to a conservative senator is not? Why are many large foundations spending a mere 5 percent of their assets each year when they can easily afford to spend more? Why do so many foundations exist in perpetuity, instead of “spending down” and closing their doors? Why is the sector so lightly regulated by government, particularly the IRS? Finally, what exactly is the public getting in exchange for colossal tax breaks granted for philanthropy, which mainly go to rich people?

The Givers, which went to press before Donald Trump was elected, concludes with a stark and prescient warning: the nonprofit sector should initiate its own reforms, before politicians do it with a heavier and more mischievous hand. “It’s not okay,” he warns, “to settle for a status quo in which the foundation world remains forever a black box.” His proposals for change—the creation of a new U.S. federal office of charitable affairs, a reevaluation of what should qualify for tax-exempt status, trustee boards that are more inclusive and transparent—are not likely to be embraced in Trump’s Washington, however.

Katz, writing after Trump’s victory, argued that Callahan has sidestepped the central issue: Our current dire political situation is the product of both traditional American anti-statism and a very different and deliberate assault on the state by plutocrats. We do not have so many billionaires, and thus mega-foundations, because we now have a larger and more adept entrepreneurial class, but because the structure of (mostly federal) economic policy has been captured by people of wealth, who have rewritten the laws to enable themselves to become extraordinarily rich…It seems to me that the new plutocrats are in fact the problem, and they are quite unlikely to be part of the solution, as Callahan contends.

My own wish is that Callahan had confronted, in a more pungent way, the structural features of the behemoth that looms before him: the grant-making model itself, upon which modern American philanthropy rests. Foundation leaders advocate transparency, inclusion, and equality, but they operate in a strikingly hierarchical manner. They are a cloistered elite.

Does this top-down model—in which grantees spend immense time and energy chasing cash—inhibit the growth of dues-paying organizations, which may be more vibrant and democratic than nonprofit organizations dominated by an aloof board of trustees and an executive director? Passages in The Givers suggest that Callahan has pondered these matters, but he stops short of a full critique.

There are now more than ninety thousand private foundations, whose assets total $700 billion. These foundations supply money to more than a million tax-exempt, nonprofit organizations. Some of these nonprofits are financially secure, but many chafe under immense anxiety as they await annual grants from their masters in the foundation suites.