Then the generalizations: hoo boy. At one point during World War II, Diamond says, the people of Finland, facing Soviet bellicosity, “were unanimous in refusing to compromise further.” A whole nation, unanimous! We learn of another instance of 100 percent society-wide agreement down under, where “Australians debating the federal constitution argued about many matters but were unanimous about excluding all nonwhite races from Australia.” But in fact they argued about this issue, too, and one framer, Andrew Inglis Clark, the Tasmanian attorney general, sought, unsuccessfully, to introduce an adapted version of the American 14th Amendment, which would have prohibited discrimination by race.

In claiming that Germany has become more socially liberal, Diamond claims, “There is no spanking of children; in fact, it’s now forbidden by law!” But how can a serious thinker confuse the passage of a law with fidelity to it? An organization that tracks the efficacy of the law has found its enactment to have reduced, but hardly ended hitting. To read Diamond is also to learn, apparently, how all Chileans identify (with Europe and the United States, not Latin America); and how all “Indonesians take their national identity for granted.” (Except, perhaps, the separatist groups?)

Sometimes the book feels written from a drying well of lifelong research rather than from the latest facts. For example, Diamond tells us Americans have always been a highly mobile people and are “unlikely” to “move less often.” He must be unfamiliar with the rather well-publicized new data declaring the opposite: “Fewer Americans Are Moving to Pursue Better Jobs Across the Nation,” NPR says, citing the Census Bureau’s research that the number of Americans who move in a given year has dropped by half since the 1940s.

There are far more of these errors than I have space to list, too many to dismiss this calling-out as nit-picking. And they matter because of the book’s nature. If we can’t trust you on the little and medium things, how can we trust you where authors of 30,000-foot books really need our trust — on the big, hard-to-check claims? On how the end of the White Australia policy “resulted from five considerations.” (Not four, not six, and the ones you happen to name.) On how Finns’ love of their language is what made them willing to fight and die for Finland. On how Tokyo is clean “because Japanese children learn to be clean and to clean up” (and not, for example, because the city spends 3.9 percent of its budget on public health and sanitation, according to a quick search, compared with the 1.9 percent of New York City’s 2018 budget that went to the Department of Sanitation).

While “Upheaval” does list sources in the back, Diamond seldom quotes books. He is far fonder of quoting his many friends. “Why does Japan pursue these stances? My Japanese friends suggest three explanations.” That’s what we’re going with? Or he describes “the 1973 coup that many of my Chilean friends characterize as inevitable.” First of all, why are we paying you to hear your friends’ random theories? Second of all, how can a coup ever be inevitable? You mean to say that a plot as delicate as that could under no scenario have gone wrong?

Since we’re talking about our friends, I know so many younger writers, especially women and people of color, who are smart, thoughtful, buttoned up and pretty damn accurate who would kill for an opening to publish a book with a serious publisher — and who know in their bones that, if they were ever this sloppy, their career would be over before it had even begun.

There is also a systemic issue here. The time has come for those of us who work in book-length nonfiction to insist that professional fact-checking become as inalienable from publishing as publicity, marketing and jacket design — and at the publisher’s expense rather than as a cost passed on to the author, who, understandably, will often choose to spend her money on health care. In the age of tweets, it cannot be the fate of the book to become ever more tweetlike — maybe factual, maybe whatever. The book must stand apart, must stand above.