If there is any lingering uncertainty that the Koch brothers are the primary sponsors of climate-change doubt in the United States, it ought to be put to rest by the publication of “Kochland: The Secret History of Koch Industries and Corporate Power in America,” by the business reporter Christopher Leonard. This seven-hundred-and-four-page tome doesn’t break much new political ground, but it shows the extraordinary behind-the-scenes influence that Charles and David Koch have exerted to cripple government action on climate change.

Leonard, who has written for Bloomberg Businessweek and the Wall Street Journal, devotes most of the book to an even-handed telling of how the two brothers from Wichita, Kansas, built up Koch Industries, a privately owned business so profitable that together they have amassed some hundred and twenty billion dollars, a fortune larger than that of Amazon’s C.E.O., Jeff Bezos, or the Microsoft founder Bill Gates. The project took Leonard more than six years to finish and it draws on hundreds of hours of interviews, including with Charles Koch, the C.E.O. and force without equal atop the sprawling corporate enterprise. (David Koch retired from the firm last year.)

While “Kochland” is more focussed on business than on politics, in line with Leonard’s “The Meat Racket: The Secret Takeover of America’s Food Business,” from 2014, it nonetheless adds new details about the ways in which the brothers have leveraged their fortune to capture American politics. Leonard shows that the Kochs’ political motives are both ideological, as hardcore free-market libertarians, and self-interested, serving their fossil-fuel-enriched bottom line. The Kochs’ secret sauce, as Leonard describes it, has been a penchant for long-term planning, patience, and flexibility; a relentless pursuit of profit; and the control that comes from owning some eighty per cent of their business empire themselves, without interference from stockholders or virtually anyone else.

Saying anything new about the Kochs isn’t easy. The two brothers have been extensively covered: they are the subject of Daniel Schulman’s excellent biography “Sons of Wichita,” from 2014, and the focus of much in-depth investigative reporting, including a piece I wrote for The New Yorker, from 2010, and my book “Dark Money: The Hidden History of the Billionaires Behind the Rise of the Radical Right,” from 2016.

Leonard, nonetheless, manages to dig up valuable new material, including evidence of the Kochs’ role in perhaps the earliest known organized conference of climate-change deniers, which gathered just as the scientific consensus on the issue was beginning to gel. The meeting, in 1991, was sponsored by the Cato Institute, a Washington-based libertarian think tank, which the Kochs founded and heavily funded for years. As Leonard describes it, Charles Koch and other fossil-fuel magnates sprang into action that year, after President George H. W. Bush announced that he would support a treaty limiting carbon emissions, a move that posed a potentially devastating threat to the profits of Koch Industries. At the time, Bush was not an outlier in the Republican Party. Like the Democrats, the Republicans largely accepted the scientific consensus on climate change, reflected in the findings of expert groups such as the Intergovernmental Panel on Climate Change, which had formed in 1988, under the auspices of the United Nations.

The Kochs’ key role in stopping congressional action on climate change is well-known, but longtime environmental activists, such as Kert Davies, the director of the Climate Investigation Center, credit Leonard with discovering that the Kochs played an earlier and even more central role in climate-change denial than was previously understood. In 2010, Davies authored a report, for Greenpeace, that labelled the Kochs “The Kingpins of Denial,” but he told me that he hadn’t realized that their role went as far back as 1991. (A copy of a flyer for the Cato conference can be seen at Koch Docs, a new digital collaborative-research project, directed by the liberal corporate watchdog Lisa Graves, which tracks the Kochs’ influence.)

According to “Kochland,” the 1991 conference was called “Global Environmental Crisis: Science or Politics?” It featured many of the same characters who have spread doubt about the reality of climate change and continue to challenge the advisability of acting against it. Among the speakers was Richard S. Lindzen, a professor of meteorology at M.I.T., who is quoted in the brochure as saying there was “very little evidence at all” that climate change would be “catastrophic.”

“Kochland” is important, Davies said, because it makes it clear that “you’d have a carbon tax, or something better, today, if not for the Kochs. They stopped anything from happening back when there was still time.” The book also documents how, in 2010, the company’s lobbyists spent gobs of cash and swarmed Congress as part of a multi-pronged effort to kill the first, and so far the last, serious effort to place a price on carbon pollution—the proposed “cap and trade” bill. Magnifying the Kochs’ power was their network of allied donors, anonymously funded shell groups, think tanks, academic centers, and nonprofit advocacy groups, which Koch insiders referred to as their “echo chamber.” Leonard also reports that the centrist think tank Third Way quietly worked with the Kochs to push back against efforts to renegotiate the North American Free Trade Agreement, which could have affected their business importing oil from Canada. Frequently, and by design, the Koch brothers’ involvement was all but invisible.

Others have chronicled the cap-and-trade fight well, but Leonard penetrates the inner sanctum of the Kochs’ lobbying machine, showing that, from the start, even when other parts of the company could have benefitted from an embrace of alternative energy, Koch Industries regarded any compromise that might reduce fossil-fuel consumption as unacceptable. Protecting its fossil-fuel profits was, and remains, the company’s top political priority. Leonard shows that the Kochs, to achieve this end, worked to hijack the Tea Party movement and, eventually, the Republican Party itself.

Scientists who worked for Koch Industries adopted the company line; Leonard quotes a former company scientist, who embraced the conspiracy theory that élites invented a global-warming “hoax” as a way to unite Americans against a common enemy after the Cold War. Leonard also quotes Philip Ellender, Koch Industries’ top lobbyist, as claiming, in 2014, that the Earth had gotten cooler in the previous eighteen years. In fact, according to NASA, eighteen of the nineteen hottest years on record have occurred in the past two decades. Yet the Koch machine bought its way into Congress and turned climate-change denial into an unchallengeable Republican talking point. Meanwhile, after the cap-and-trade bill died, the planet continued heating, and the Kochs’ net worth doubled.

Because the Kochs opposed the candidacy of Donald Trump, in 2016, many have assumed that they are antagonistic to the Trump Administration. To the contrary, Leonard writes, with the help of allies such as Vice-President Mike Pence, “the politics that the Kochs stoked in 2010 became the policies that Trump enacted in 2017.” Whether announcing his intention to withdraw from the Paris climate accord, placing shills from the oil and coal industries at the head of federal energy and environmental departments, or slashing taxes on corporations and the ultra-wealthy, Trump has delivered for the Kochs. “Kochland” quotes Charles Koch telling his allied political donors, in 2018, “We’ve made more progress in the last five years than I had in the previous fifty.”

Leonard’s grasp of political details isn’t always completely firm. He describes the late Senator Arlen Specter, a moderate from Pennsylvania, as being a “conservative” Republican prior to his switch to the Democratic Party. And Leonard misconstrues the origin of the term “Kochtopus,” which was coined not recently by political critics but decades ago by rival libertarians who derided the Kochs for putting self-interest above principle. But “Kochland” is deeply and authoritatively reported, and, while it can be overly cautious in the conclusions that it draws, it marshals a huge amount of information and uses it to help solve two enduring mysteries: how the Kochs got so rich, and how they used that fortune to buy off American action on climate change.