How do we explain to the new, knowing wash-ashores, Brits and Aussies mainly, who have insinuated themselves into the media here, and into popular American culture generally, and to the very young, that there are touchstones and events that define us, that have formed us, that they know nothing about? They don’t have the slightest clue, nor do they know Bo Diddley.

In my own life, the most shocking event, overwhelming everything else, was the lynching of Emmett Till in 1955, then the assassinations — John Kennedy, Robert Kennedy and Martin Luther King. These horrors, along with vivid marginalia, “The Great Gildersleeve” on radio; Phil Silvers and the Army-McCarthy hearings on television; the senior prom; the Thanksgiving Day football game; Chuck Berry’s “Maybellene”; and in literature, for me, “Tropic of Cancer,” “Peyton Place,” “Generation of Vipers” and “The Lottery.”

An essay could be written about the occasions, big and small, that occupy the collective unconscious of the average American who came awake in the 1940s. It is proof of the power of Shirley Jackson’s story that it was still resonating in Miss Bagley’s English class when I was a student at Medford High in the late 1950s. It electrified the readers of The New Yorker when it was first published in June 1948 and — I reread it the other day — it still sends chills, reminding us just how potent and inspiring a short story can be.

“I remember one spring morning I was on my way to the store,” Shirley Jackson writes in an essay in “Let Me Tell You,” this new collection of fiction and nonfiction, “pushing my daughter in her stroller, and on my way down the hill I was thinking about my neighbors, the way everyone in a small town does. The night before, I had been reading a book about choosing a victim for a sacrifice, and I was wondering who in our town would be a good choice for such a thing.”

After that explosive story came her first collection, with “The Lottery” as the title story. And in 1959, with her novel “The Haunting of Hill House,” she established herself firmly in the American Gothic tradition. Three years later came the equally strong novel “We Have Always Lived in the Castle” and then, with the exception of some stories and sketches, nothing more. She died in 1965 at the age of 48. The centenary of her birth is next year.

For those of us whose imaginations, and creative ambitions, were ignited by “The Lottery,” Jackson remains one of the great practitioners of the literature of the darker impulses and (in a term she uses in “Hill House”) “the underside of life.” The texture of her two major novels tends to lushness and formality, more verbal foliage, while her stories are plain-spoken and persuasive for their apparent ­directness.

What we have here are 30 short stories (22 of which have never been previously published), 10 humorous bits of family memoir and 16 essays and talks, nearly all of them in print for the first time. The stories range from sketches and anecdotes to complete and genuinely unsettling tales, somewhat alarming and very creepy. None can be called terrifying, nor can any be ranked with Jackson’s best work, yet the whole of the book offers insights into the vagaries of her mind, which was ruminant and generous, accommodating such diverse figures as Dr. Seuss and Samuel Richardson — and managing to succeed at something many English majors fail at, finishing both “Pamela” and “Clarissa.”

The helpful chronology provided by Joyce Carol Oates in “Shirley Jackson: Novels and Stories,” the Library of America’s volume that collects the major novels and the best stories, indicates that Jackson’s life, although mostly sunny, clouded over in her last decade. Some of the pieces here recount her happy marriage to the critic Stanley Edgar Hyman, who became an energetic booster of her work. The couple rusticated themselves to Bennington, Vt., where he was a teacher and she — as far as the neighbors knew — was a housewife, raising four talkative children. ­Ultimately, for various reasons, the neighbors took against them. Oates’s 1956 entry in the Jackson chronology provides details: “In this and coming years, townsfolk will harass the Hymans with anonymous hate mail, soap their windows with swastikas and repeatedly dump garbage into the bushes lining their front sidewalk.”

You associate the Green Mountain State with gourmet ice cream and cows, not swastikas and hate mail, but on second thought it’s possible to conclude that such small town infernality is very ­Jacksonian. A version of this village small-mindedness and hostility is a feature of “We Have Always Lived in the Castle,” but no mention of any of this appears in the jolly reports and family reminiscences that are included here. The titles are self-explanatory: “Here I Am, Washing Dishes Again,” “Mother, Honestly!” “The Pleasures and Perils of Dining Out With Children” and half a dozen more, most of them chirpy, with the sigh of fun-poking exasperation you associate with Erma Bombeck, whose columns these much resemble. We will have to wait for next year’s promised biography by Ruth Franklin, who wrote the foreword to this volume, to know how deeply Jackson was affected by the harassment and the shunning.

One consequence was Jackson’s increasing reclusiveness. This shows in the uneven stories, and they add proof to my theory that lesser works reveal much more of the writer’s mind and circumstances than finished and finely wrought fictions. What is Jackson’s landscape? Where are the road trips and the open skies and the noodle salad in the picnic area? They do not exist. Hers are fictions of interiors; her world is a house — an ideal cast of mind for someone writing ghost stories. And the larger the house, the more numerous the rooms, the greater the possibility for menace. It’s obvious that Jackson kept herself to her house and then made something of it — sometimes denying its misery with her litany of domestic satisfactions and jollifications, at others making it into darkness, in the tone of the captive she presumably felt herself to be.

Even an exterior, big-city story like “Paranoia” — one of the best here — is given its impetus by conveying the impression that the man being stalked is trapped, confined by busy streets and brooding buildings. Another urban story, “The Arabian Nights,” takes place in a nightclub and has an odd juxtaposition — a family hectoring a young girl to talk to a man who looks like, and might be, Clark Gable. “Family Treasures,” which takes place in a college ­dormitory, is the tale of an innocent-­seeming kleptomaniac. “The Lie,” as with many others, is a story about insecurity. “The Sorcerer’s Apprentice” features a wicked child. A group of stories that predate “The Lottery” are set at the close of World War II: “The Paradise,” “The Homecoming,” “Daughter, Come Home” and “As High as the Sky.” What the wartime ones have in common is melancholy, unease and especially a sense of separation bordering on alienation, the territory of her like-minded near-contemporary the Alabama novelist and short story writer William March, who is remembered only for his last novel, “The Bad Seed.”

Although some of what appears in this collection, culled from the Jackson archives by two of her children, is clearly from the bottom drawer, the assortment is large enough to contain much that is satisfying. It shows the many directions her writing took and provides many tantalizing asides. At one point, she mentions something she intended to write, “a long story about a girl who runs away from home and tries so successfully to eradicate any aspect of her old personality that when she wants to go home again she can’t get in; they don’t know her.” This fetching idea is the general concept of Albert Camus’s “Le Malentendu.” I wonder if she ever wrote it?