I first encountered the work of Roald Dahl in third grade, by playing a character in a classroom adaptation of “Charlie and the Chocolate Factory.” Not long after that, I read “James and the Giant Peach.” I was not a child who particularly cared for children’s literature, but even as an eight- or nine-year-old I was captivated by the way Dahl’s fantasias took on their own logic, their own momentum, and were driven as much by the flow of language as by the absurdities of plot. Put another way, reading Dahl was my introduction to the importance of the teller, the idea that a successful story was less a matter of narrative than of voice—or not less, exactly, for Dahl’s writing is nothing if not plotted. But he made me aware that the narrator, whether third person or first, is not a neutral figure but an active, even directive, force. (This discovery may have had something to do with the role I played in “Charlie and the Chocolate Factory”: I was the narrator.)

Dahl died, in Oxford, England, in 1990, at the age of seventy-four, and this September marks the centennial of his birth, in Cardiff, Wales. More than two hundred million copies of his books are in print, and they have inspired countless adaptations, most recently the Steven Spielberg film “The BFG,” based on Dahl’s 1982 book of the same name, about an orphan girl named Sophie—bad fortune, complete with adversarial adults and minders, is a staple of his writing for young readers—who, one night, witnesses the BFG, or “big friendly giant,” of the title, blowing dreams into the windows of sleeping children. This is among my favorite Dahl books, in part because of the giant’s idiosyncratic language (he likes a drink called “frobscottle,” which causes flatulence, or “whizpopping”) and in part because I used to read it to my daughter, also named Sophie, when she was small. This suggests something, I think, about why his work for children lingers: a whisper of nostalgia, a bit of history, personal or otherwise. Still, as Dahl also understands, nostalgia only goes so far, for childhood is a passing phase. “I’m wondering what to read next,” Matilda, another one of his beloved title characters, says, as if to make such an idea explicit. “I’ve finished all the children’s books.”

Dahl may as well have been writing about himself: “Matilda” was the last of his children’s books to appear, just two years before his death. I can’t help but read this in a different way, however, as if it were a coded reference to Dahl’s four books of adult short stories. The first, “Over to You,” came out in 1946, and features ten not-quite-conventional combat stories, based on his experience as a pilot in the Royal Air Force during the Second World War. That book was followed, in 1954, by “Kiss, Kiss” and, in 1960, by “Someone Like You,” which together include, among other pieces, ten stories that originally appeared in The New Yorker. The writing relies on wicked twists: the sickly infant, saved, who grows up to be Adolf Hitler; the visitor to a taxidermist’s bed-and-breakfast who discovers, too late, the taste of bitter almonds in his tea. A similar perspective marks Dahl’s final collection, “Switch Bitch,” four longer stories of sexual indiscretion, first published in Playboy. This is not the Dahl of the children’s books, but, at the same time, of course it is. Here, too, we find the irreverent pleasure in the telling, the attitude of moral justice, the pointedness of the voice. And yet these stories remain largely overlooked. Writing for adults is not what we think about when we think about Dahl—it does not fit our caricature of him. Even as we acknowledge his difficulties—he was, as Sam Anderson wrote in New York, in 2010, “a stereotypical mid-century wealthy imperial Brit—a bullhorn of prejudice and entitlement whose gaffes could be almost touchingly clueless”—we want, it seems, for him to fit a kinder, gentler formula. His adult writing roughs out the smoothness of his edges. (Even Anderson dispenses with it in little more than a paragraph.)

There are fifty-one of them, found most easily in his “Collected Stories” (which gathers all four collections as well as a few scattered stand-alones), and, in these pages, we encounter a voice we recognize, pushing the boundaries of the so-called normal, beginning in a hotel or English drawing room before spinning out in unexpected ways. In “Royal Jelly,” a beekeeper feeds his underweight infant daughter royal jelly from his hives only to see her turn “fat and white and comatose, like some gigantic grub that was approaching the end of its larval life and would soon emerge into the world complete with mandibles and wings.” Similarly, “Man From the South” opens with a simple wager: an older gentlemen bets a young American he can’t spark his lighter ten straight times. If the American wins, he gets a Cadillac; if not, he agrees to have his left pinkie removed. Before the contest can conclude, however, it is interrupted by the gentleman’s travelling companion, who insists he has already lost all his possessions and then proves it by putting her hand on the table: “it had only one finger on it,” Dahl writes, “and a thumb.” We might call this a twist upon a twist, in the style of O. Henry, or better yet of Saki, whose writing Dahl’s sometimes recalls. At the same time, Dahl comes off as more knowing, or perhaps more winking, as if he and we, a writer and his readers, were in cahoots together. For him, the act of storytelling, at its heart, is a collaborative game.

Such a posture of collaboration, of conversation, marks the bulk of Dahl’s fiction, whether for children or adults. It’s one of the pleasures of reading him, that for all the callowness, or cruelty, of his characters, he never extends his judgments onto us. Think of Aunts Sponge and Spiker, in “James and the Giant Peach”; Miss Trunchbull, in “Matilda”; or Augustus Gloop and Veruca Salt, in “Charlie and the Chocolate Factory.” Even as they get their comeuppance, in gruesomely inventive fashion, Dahl’s wit and charm, his pure pleasure in the narrative, remain the most memorable and salient quality. The same is true of “The Way Up to Heaven,” in which a put-upon wife leaves her husband stuck between floors in the elevator of their Manhattan townhouse while she goes to Paris for six weeks, or “Lamb to the Slaughter”—perhaps his best-known work for adult readers—in which another wife kills her unfaithful husband by beating him over the head with a frozen leg of lamb, which she then offers to the police detectives who come to investigate. “You must be terribly hungry by now because it’s long past your supper time, and I know Patrick would never forgive me, God bless his soul, if I allowed you to remain in his house without offering you decent hospitality,” she says.

For all that such turnabouts come off as punch lines, it would be inaccurate to say that Dahl writes without a heart. As with his books for children, his adult stories are marked by conscience, by a moral center that extends beyond mere payback, leading to moments of unexpected depth. Take “Poison,” for instance, which involves an elusive kind of venom—that of racism and hate. The setup is straightforward: a man, living in India, returns home to find his housemate in bed, frightened and frozen, a deadly snake beneath the sheets. He calls a local doctor, who pumps chloroform into the bed and removes the covers, at which point no snake is found. Rather than providing relief, this leads to conflict when the doctor suggests a mistake may have been made. “Are you calling me a liar?” the housemate asks, before launching into ugly invective: “Why you dirty little Hindu sewer rat!” There is no twist here, no surprise ending, no comeuppance except for the discomfort of the doctor and the narrator. “Don’t you listen to Harry,” the latter insists, but the doctor cannot meet his eye, and the story ends with the sense that nothing has, or can be, reconciled. A similar attitude of loss and longing marks “The Wish,” about a child who imagines, with devastating results, that his mother’s patterned carpet is a snake pit, or “Only This,” in which a mother dreams her way into a bomber that her son is flying, only to die, as he does, when the plane is shot down. Most moving, perhaps, is “Mr. Botibol,” the saga of a lifelong failure who finds unexpected fulfillment and connection in pretending to conduct the great symphonies and concertos of Beethoven and Chopin.