With respect to corruption, a distinction is made between the fleecing of public resources that underpinned the fortunes of many of the earliest Indian billionaires and an equally “grand but more orderly” form of corruption in which the spoils are used to fund social progress and encourage growth. The latter is treated sympathetically, although the lines between the many forms of corruption described are far from clear.

Mr. Modi has done much to reduce some of the most flagrant forms of corruption, but at the price of a disturbing increase in nationalism and a Trumpian authoritarian streak. Although Mr. Crabtree credits Mr. Modi with having “reset the balance of power between politics and business,” he concedes that “kickbacks still dominate swaths of public life.” Despite these and a variety of other concerns about the current regime, he concludes that Mr. Modi’s victory “rebuffed the notion that India itself had grown ungovernable, as if its turbulent democracy had become such a drag on its economy that it could not follow China’s rapid process of development.”

Although there may be cause for such optimism, I could not find it in the pages of “The Billionaire Raj.” Only 30 years ago, the economies of China and India were roughly the same size. China’s economy is now almost five times as large, and at India’s current growth rate, it would take decades for India to reach China’s current size.

As Mr. Crabtree’s narrative makes plain, the primary source of financial corruption — the immovable rot at the base of the Indian economy — is “the exorbitant and rapidly rising election costs for political parties, which has pushed them to raise huge quantities of illicit funds.” A candidate in a close parliamentary race must raise at least $1 million, a monumental sum that is largely unachievable without some illicit quid pro quo. It is hard not to conclude that India’s turbulent democracy poses a serious threat to its future development. If you want to feel better about our own problems in the face of the Supreme Court’s decision in Citizens United, read “The Billionaire Raj.”

Mr. Crabtree believes “there is no reason” that India’s current Gilded Age cannot “blossom into a Progressive Era of its own, in which the perils of inequality and crony capitalism are left decisively behind.” The nuanced portrait of contemporary India that he has provided may not support this level of confidence, but I can’t help but agree with Mr. Crabtree that “the world’s hopes for a more democratic, liberal future” very much depend on India’s “getting this transition right.”