This, as much else here, does not make for pleasant reading. Vonnegut was Whitmanesque, contradictory, containing multitudes. As a parent, he could be sweet and generous but also aloof, and even, according to one nephew, “cruel” and “scary.” When his sister died of cancer within a day of her husband’s ghastly death in a train wreck, Vonnegut and his wife raised three of their four orphaned children. But the domestic scenes don’t read like “Cheaper by the Dozen.” As a dad, Vonnegut was a mixed blessing.

Shields has a deep affection for his subject and does what he can to rebut charges of hypocrisy, but in this he is not entirely convincing. Vonnegut the staunch anti-Vietnam War spokesman couldn’t be bothered to help his wife campaign for Eugene McCarthy; more disconcerting is the revelation that as an avid purchaser of stocks he had no qualms about investing in Dow Chemical, maker of napalm. At the least, it seems an odd buy for a survivor of the Dresden firebombing. The champion of saving the planet and the Common Man also, we learn, owned shares in strip mining companies, malls and corporations with antiunion views. So it goes.

As a writer of science fiction — a label he tried strenuously to shed, not wanting his books to be shelved in the genre ghetto — he was curiously blasé, even antagonistic, about the moon landing on July 20, 1969. On a broadcast with Walter Cronkite, Gloria Steinem and others, he dissed the entire enterprise and reiterated his view that the $33 billion should have been spent “cleaning up our filthy colonies here on Earth.” The avuncular Cronkite let it go, but CBS was swamped with furious letters. (For the record, many of the writers felt that Steinem too had been “un-American.”)

But this was echt Vonnegut: not with a bang or a whimper but with a shrug. If he, like Twain, was angry at the universe — and had every reason to be — he wasn’t going to yell himself hoarse or make himself a spectacle in the process. He possessed more ambivalence than passion; odd, perhaps, in someone of German ancestry. (Seems more . . . French.) But then the line with which he will always be remembered, from “Slaughterhouse-Five,” is “So it goes,” as close an English-­language phrase as there is to denote hunching shoulders.

As to whether he wrote for the kids, or for — pardon — kids of all ages, and for the ages, perhaps that’s more definitively answered by the Library of America’s recent publication of “Kurt Vonnegut: Novels and Stories 1963-1973,” ably edited by Sidney Offit. Turning to the first sentences of “Slaughterhouse-Five”:

“All this happened, more or less. The war parts, anyway, are pretty much true. One guy I knew really was shot in Dresden for taking a teapot that wasn’t his. Another guy I knew really did threaten to have his personal enemies killed by hired gunmen after the war. And so on. I’ve changed all the names.”

There’s an echo there of another voice — Holden Caulfield’s, and didn’t the guy who came up with him also have a reputation for writing for kids?