Author Natalie Babbitt died Oct. 31, 2016, at 84. (Family photo)

Natalie Babbitt, a celebrated author of children’s literature whose 1975 novel “Tuck Everlasting” led millions of young readers on an exploration, both fantastical and philosophical, of what it might mean to live forever, died Oct. 31 at her home in Hamden, Conn. She was 84.

The cause was lung cancer, said her husband, Samuel Fisher Babbitt.

Mrs. Babbitt wrote or illustrated more than two dozen books, among them “Kneeknock Rise” (1970), a recipient of the Newbery Honor. But she was best known for “Tuck Everlasting,” a volume that became required reading in many schools and a favorite of children and parents alike. Novelist Anne Tyler once described it as “one of the best books ever written — for any age.”

Set in the town of Treegap at the turn of the 20th century, the novel centers on a girl, Winnie Foster, who befriends the Tuck family. To her awe, Winnie learns that the Tucks have drunk from a spring that confers eternal life — and that if the water is not a curse, it is not a blessing, either.

The family must contend with a menacing unnamed man, recognizable by his yellow suit, who sets out to sell the water as an elixir, not minding the isolation that comes with its spell. And while one Tuck son wishes that Winnie will drink from the spring and be his eternal love, his father tries to save her from the water’s allure.

“Dying’s part of the wheel, right there next to being born,” he tells her. “You can’t pick out the pieces you like and leave the rest. Being part of the whole thing, that’s the blessing. But it’s passing us by, us Tucks.”

“If I knowed how to climb back on the wheel, I’d do it in a minute,” he continues. “You can’t have living without dying. So you can’t call it living, what we got. We just are, we just be, like rocks beside the road.”

Mrs. Babbitt once told Publishers Weekly that everything in the book “comes from actually living it.” Treegap and the surrounding area was based on a refuge in the Adirondacks where she vacationed. She wrote the book for her 4-year-old daughter, who one day awoke from a nap crying and afraid, her mother discerned, of death.

“It seemed to me that that was the kind of thing you could be scared of for the rest of your life,” Mrs. Babbitt told NPR years later. “And it seemed to me that I could write a story about how it’s something that everybody has to do and it’s not a bad thing.”

“Tuck Everlasting” was quickly recognized as a classic. “The story is macabre and moral, exciting and excellently written,” Philippa Pearce, a children’s author, wrote in a New York Times review. “It has no absolute end, because Time hasn’t.”

The book, like the Tucks, proved ageless. It was adapted into a film in 1981 and again in 2002, with William Hurt and Sissy Spacek as the Tucks, Alexis Bledel as Winnie and Ben Kingsley as the man in the yellow suit. The novel also inspired a short-lived Broadway musical this year. A moral — or at least one unmuddied by questions — proved elusive.

“People are always looking for a lesson in it, but I don’t think it has one,” Mrs. Babbitt said in an interview with Scholastic. “It presents dilemmas, and I think that’s what life does! . . . I think a lot of adults would like to think that things are simple for kids, but that’s not so.”

Natalie Zane Moore was born in Dayton, Ohio, on July 28, 1932. Her father was a businessman, and her mother was an amateur painter.

Inspired by her mother, she said she knew from an early age that she wanted to be a book illustrator. She was a 1954 art graduate of Smith College in Northampton, Mass.

Her first illustrations appeared in “The Forty-Ninth Magician” (1966), a picture book with text by her husband. After an editor suggested that Mrs. Babbitt pursue her own writing, she wrote several volumes in verse, eventually moving into chapter books.

Her early titles included “The Search for Delicious” (1969), set in a magical kingdom complete with king, queen and mermaid. Next came “Kneeknock Rise,” about a mountain-dwelling monster that may be symbolic or real.

Like “Tuck,” “The Eyes of the Amaryllis” (1977), about a widow who waits decades for her husband lost at sea, was adapted for film.

Mrs. Babbitt said her favorite book that she had written for children was “Goody Hall” (1971), a Gothic mystery with a happy ending, and that her favorite book overall was “Herbert Rowbarge” (1982), an adult novel about a man separated from his twin as a baby.

Her most recent book was “The Moon Over High Street” (2012), about an orphan who must choose between following his dream, however obstacle-strewn, of becoming an astronomer or being adopted by a millionaire who may not be able to offer him a happy life.

Survivors include Mrs. Babbitt’s husband of 62 years, Samuel Fisher Babbitt of Hamden; three children, Christopher Babbitt of Hudson, Wis., Thomas Babbitt of Brunswick, Maine, and Lucy Babbitt of Stratford, Conn.; and three grandchildren.

Once, Mrs. Babbitt was asked why she let Winnie decline the magical water and die in “Tuck Everlasting.”

“Winnie did what I would have done,” Mrs. Babbitt told Scholastic. “I think that living forever would be a terrible thing. It would be boring, sad and lonely.”