“How did you go bankrupt?” one character asks another in Hemingway’s “The Sun Also Rises.” “Gradually and then suddenly,” comes the reply that has been latterly used to characterize crises from the coronavirus to climate change to Israel.

Well, it works too for dementia: that dull and darkening cloud that will dim more and more people’s lives as baby boomers enter old age. “An insidious fog, barely noticeable until everything around has disappeared,” the literary critic John Bayley called it in “Elegy for Iris,” his 1998 memoir of a vivid marriage to the novelist Iris Murdoch that was blurred by her Alzheimer’s diagnosis.

Alzheimer’s is the most common variant of dementia, like tequila is to mezcal — both of which might come in handy if you are helping care for someone with the disease.

I’ve watched some version of it descend on both of my parents (hi Mom, for whom the print edition of The New York Times remains a blessed daily guidepost). Small incidents accumulate, snowflakes falling on the ground. A credit-card bill unpaid; a date forgotten; an episode of disorientation at a familiar train station — these might get excused and melt away. Then one day you wake up and realize you’re in a full-on blizzard.

America’s health care system being what it is, you might also be about to go bankrupt.

Bayley’s rippling allusiveness, from Tolstoy to the Teletubbies, is hard to match. But the best of this year’s books about dementia — and there will be many more in years to come — also invoke literature, art and pop culture to help explain what science and medicine, in all their lab-coated well-meaningness, cannot fully. (How we’ll pay for it all is a topic for another department.)

“Stephen King could not have designed a better plot for a sickness that slowly steals the mind, then pilfers the body, then robs your finances,” writes Greg O’Brien, a journalist diagnosed with early-onset Alzheimer’s, in Joe Wallace’s THE DAY AFTER YESTERDAY: Resilience in the Face of Dementia (MIT Press, 168 pp., $34.95). O’Brien refers as well to “Alice in Wonderland,” Mr. Magoo, Pac-Man (munching brain cells instead of digital pellets) and — again — Hemingway, this time “A Farewell to Arms.”

Wallace is a photographer whose portraits of dementia patients — sometimes posed with their spouses or children — have been in a traveling exhibit throughout Massachusetts and elsewhere for a couple of years. They are straightforward, ennobling and often quite glamorous, not so many degrees off from Marion Ettlinger’s famous author photos.

This is apt, because one thing the disease does is turn its sufferers into fictionists. They might tell the same stories over and over, like audiobook narrators on endless repeat — but also, they make things up, or in clinical terms, confabulate. One of the major debates of caregiving — one of those Hallmark compound words I have come to loathe almost as much as “storytelling” — is whether to play along with these fictions or correct them in the name of a well person’s idea of trust and truth.

Crucially, “The Day After Yesterday,” its title the utterance of a former theater teacher with early-onset Alzheimer’s trying to make sense of time, includes photos of its subjects’ earlier selves: a onetime antiques dealer who met her husband after crawling under a tablecloth at a dinner party; a broad-smiling Bostonian who can’t remember the 25 years she worked assembling phone books for New England Telephone; a former homeland security analyst cogent enough to compare her condition to “mini acid trips.”It’s a jolting corrective to the default euphemizing (including by Wallace) of dementia and other incurable diseases as a “journey.”

“I hate calling it a journey because it’s not really a journey,” the drama teacher’s wife says. “It is and it’s not. It’s an experience.” Somehow Dasha Kiper’s TRAVELERS TO UNIMAGINABLE LANDS (Random House, 272 pp., $28), avoids the word altogether. The title is taken from the neurologist and writer Oliver Sacks’s classic collection of case studies, “The Man Who Mistook His Wife For a Hat.” Though she never met Sacks, he has through his publications been a kind of spirit guide to Kiper, who once worked as a helper to a 98-year-old Holocaust survivor with Alzheimer’s, and went on to become a consulting clinical director of support groups for family members at CaringKind, an Alzheimer’s nonprofit.

Kiper’s book is particularly rich with literary references. Her elderly charge reminds her of the Jorge Luis Borges story “Funes the Memorius,” about a man burdened by remembering absolutely everything, which makes him as difficult to communicate with as one who remembers nothing. “Human memory is not geared for accuracy,” Kiper reminds us. “It’s not a tape recording of events but rather a reconstruction of them that allows us to make sense of the world.” Patients and those close to them both unwittingly conspire to keep earlier versions of the self intact.

She cites Franz Kafka’s “The Metamorphosis” to show how hard it is to dislodge families from their accustomed roles; Herman Melville’s “Bartleby the Scrivener” (its lawyer-narrator’s efforts to rouse the protagonist “disturbingly familiar to caregivers”); and Samuel Beckett’s “Waiting for Godot” to highlight the importance of “the familiar rhythms and inflections of conversation” that can “coax a dementia patient back to a reality they once shared with someone.” For my 87-year-old mother, a musician, turns of phrase set to simple tunes have proved particularly durable.

When Bayley, who died in 2015, wrote “Elegy” — and a sequel, “Iris and Her Friends” — some critics castigated him for invasion of privacy, a concern that may now seem quaint, when a few in the dementia domain even have TikTok accounts with millions of followers devoted to patients’ progress (or, less rosily, regress). MY FATHER’S BRAIN, by Sandeep Jauhar (Farrar, Straus & Giroux, 256 pp., $28) is a fascinating mixture of the medical and the personal. Jauhar, a cardiologist who has contributed to The New York Times, writes frankly about his difficulty separating out filial feeling when confronting his father’s condition. He too grasps at the liberal arts for insights: King Lear’s cry of “Who is it that can tell me who I am?”; Shakespeare’s “melancholy Jaques” in “As You Like It”; Struldbruggs of “Gulliver’s Travels,” whose author, Jauhar writes, makes “a clear nod to hippocampal degeneration.”

In one of the book’s transcendent moments, he discovers several copies of Henry Wadsworth Longfellow’s “Letters of Saint Augustine,” a poem his hard-working father loved, in the piles of his study. (“The heights by great men reached and kept/Were not attained by sudden flight/But they, while their companions slept, Were toiling upward in the night.”)

As poetry does, dementia demands that its audience, skittering along impatiently in daily life, pause and be — another loathsome word — present; alert to new associations, resistant to old grievances. It is a mystery, and a saga, a tragedy with glimmers of comedy that has inspired at least one great modern play: Kenneth Lonergan’s “The Waverly Gallery,” which in its 2018 revival showcased the great Elaine May.

Until there’s a pill to definitively forestall the fog, what can one say but let there be literature?