The Koch brothers are a ripe target: political plutocrats who have spent hundreds of millions of dollars in a decades-long effort to reshape the country and the Republican Party.

They’ve used their vast wealth to build a hydra-headed network of think tanks, lobbying shops, and “astroturf” advocacy groups to advance a philosophy that conveniently overlaps with the economic interests of their Wichita-based corporation.

None of this is exactly a secret, though. Jane Mayer’s 2010 New Yorker article and subsequent book shined a bright spotlight on how the Kochs and other wealthy patrons use their Dark Money to wield outsize influence on American politics.

What Kochland, the new book from Christopher Leonard, adds to the story is not so much an account of the ways in which the brothers spend their money, but rather, a richly reported tale of how they make it — the inner workings of one of the nation’s largest private corporations.

To be sure, the Koch brothers aren’t entirely self-made. They got a sizable head start from their father. Fred Koch, a co-founder of the far-right John Birch Society, assembled his own mini-empire of ranches, factories and oil pipelines. But Charles and David Koch supersized this fortune. They added a Minnesota refinery that was well-positioned to turn cheap, Canadian crude oil into pricey gasoline for the fuel-thirsty Midwest. Over time, they expanded into fertilizer, paper products, options trading and even greeting cards.  […]