HARTFORD, Conn. — Author Madeleine L’Engle, whose novel “A Wrinkle in Time” has been enjoyed by generations of schoolchildren and adults since the 1960s, has died, her publicist said Friday. She was 88.

L’Engle died Thursday at a nursing home in Litchfield of natural causes, according to Jennifer Doerr, publicity manager for publisher Farrar, Straus and Giroux.

The Newbery Medal winner wrote more than 60 books, including fantasies, poetry and memoirs, often highlighting spiritual themes and her Christian faith.

Although L’Engle was often labeled a children’s author, she disliked that classification. In a 1993 Associated Press interview, she said she did not write down to children.

“In my dreams, I never have an age,” she said. “I never write for any age group in mind. When people do, they tend to be tolerant and condescending and they don’t write as well as they can write.

“When you underestimate your audience, you’re cutting yourself off from your best work.”

“A Wrinkle in Time” which L’Engle said was rejected repeatedly before it found a publisher in 1962 won the American Library Association’s 1963 Newbery Medal for best American children’s book. Her “A Ring of Endless Light” was a Newbery Honor Book, or medal runner-up, in 1981.

In 2004, President Bush awarded her a National Humanities Medal.

“Wrinkle” tells the story of adolescent Meg Murry, her genius little brother Charles Wallace, and their battle against evil as they search across the universe for their missing father, a scientist.

L’Engle followed it up with further adventures of the Murry children, including “A Wind in the Door,” 1973; “A Swiftly Tilting Planet,” 1978, which won an American Book Award; and “Many Waters,” 1986.