Sitting beneath a skylight on a Sunday, Sophie Kinsella called to mind a posh, slightly weary matriarch who might appear in one of her novels. Flowing leopard skirt, check. Devoted husband who looks like Harrison Ford, check. London town house near the Thames, check.

Then Kinsella lifted her chestnut hair to show a bald patch left by treatment for a brain tumor. It was a glioblastoma, the most aggressive kind.

“I couldn’t say the word ‘cancer’ for a long time,” she said “There’s still a residual cringing, fearful disbelief.”

Kinsella, 54, is the author of 33 novels, many of them No. 1 bestsellers, including “Confessions of a Shopaholic,” which led to eight spinoffs and a movie. Her novels have been translated into 40 languages in more than 60 countries. They’ve sold approximately 48 million copies worldwide, including seven books that Kinsella wrote under her given name, Madeleine Wickham.

But, over the course of this interview, it was clear that the only numbers that matter now are closer to home. Kinsella and her husband, Henry Wickham, have been married for 33 years. They have four sons and a daughter, ranging in age from 28 to 12.

Kinsella’s symptoms started in 2022, with a series of falls. “My legs stopped working,” she said. “I started lurching around. I couldn’t walk up stairs properly.”

She’d had emergency gallbladder surgery and recovery was slow. She had headaches. She was breathless and confused. She was behaving “slightly strangely,” Wickham said. For instance, Kinsella gave him a pair of scissors and asked him to cut all her hair off. He declined.

Kinsella had been “scanned everywhere because of this and because of that,” Wickham said, but answers were elusive.

That November, he was in a cafe, waiting out a son’s choir practice, when it occurred to him that there was only one part of Kinsella’s body that had yet to be examined. Wickham went home, called her doctor and said, “Maybe I’m just being an overprotective husband, but we’ve got to have a brain scan.”

The scan showed the tumor. Initially Kinsella and Wickham only shared the news with a small circle of adult family members and confidants, wanting their youngest children’s lives to remain normal for as long possible.

On Nov. 25, 2022, she had an eight-hour surgery. “When I woke up, I couldn’t walk. I couldn’t write my name. I couldn’t balance. I couldn’t turn my head,” Kinsella said. She worried she’d never write again. “For a while, it was this crashing blow every morning. You feel OK, then you remember.”

Kinsella understands that her illness is terminal, pending recurrence, and that glioblastoma always recurs.

“When people ask how I am, I don’t take it on an existential, global level,” she said. “Because that’s too big, too complex, too changeable. Ask me one day, and I’m one thing. Ask me the next day, and I’m sobbing. Sometimes — I’m like this today — I’m laughing. Then some aspect that I hadn’t considered will hit me, and I’ll be an absolute wreck. But I can always talk about how I am today.”

For three decades, Kinsella sat at her desk and wrote 1,000 words a day. She had already written six books when she sent “Confessions of a Shopaholic,” the semi- autobiographical tale of a profligate financial journalist, to her agent, Araminta Whitley.

The novel was a departure from Madeleine Wickham’s third-person social comedies — “I just cracked up with laughter from the very start,” Whitley said — so the pair dispatched it to Kinsella’s U.K. publisher anonymously, then to international publishers under a nom de plume.

Along with novels by Helen Fielding and Marian Keyes, “Confessions” and its successors ushered in a heyday of what was known, sometimes disparagingly, as “chick lit,” characterized by pink covers, witty banter and stiletto- forward fashion. As the genre morphed into “women’s fiction” (more babies, fewer martinis), then “rom-com” (less commitment, more tattoos), Kinsella rode the wave. As she aged, her protagonists remained in their 20s and 30s, leaving readers with a sense that, while they navigated careers, midlife, motherhood and health struggles, they were still in touch with younger versions of themselves.

Now, from a prone position, Kinsella wrote what she could. She knew she didn’t want to attempt a memoir; her memory wasn’t up to the task. One day she typed up a short story about spouses taking a walk and singing Christmas carols while the wife recovers from brain surgery. It became a chapter in her recently released book “What Does it Feel Like?”

The novella unfolds in vignettes, following Eve Monroe, a successful novelist and mother of five who has cancer. While searching “Grade 4 glioblastoma” from her hospital bed, she learns that the average survival time is 12 to 18 months. There is no cure. The book is markedly less cheerful than the breezy page-turners that are her standard fare, but it’s still a love story. It’s funny, too, strange as this sounds.

Sentence by sentence, Kinsella distanced herself from fear. It never retreated, not entirely, although language was a trusty shield. She said, “It took me a while to figure out how I was going to have a happy ending, but I was absolutely determined.”

On April 17, almost a year and a half after surgery, Kinsella was ready to share news of her diagnosis with her fans. “I’ve been waiting for the strength to do so,” she wrote in an Instagram post. Readers’ responses were so supportive that she posted a video, thanking them for their kindness.

“I was like, ‘OK, at last, I can just be me now,’ ” Kinsella said. “There comes a tipping point, I think, when being private can feel like you’re hiding.”

Kinsella remains focused on the day to day — and each one begins with the same routine: “Henry gets up very early. He reads the whole internet and brings me a cup of tea and a hopeful story. He’ll say, ‘I read about someone who lasted this long after diagnosis.’ ”

She said, “I really want to be someone else’s story of hope.”