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

For many years, she was the writer in residence and librarian at the Episcopal Cathedral Church of St. John the Divine in New York City.

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 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.

Keith Call, special collections assistant at Wheaton College in Illinois, which has a collection of L'Engle's papers, said he considers her the female counterpart of science fiction author Ray Bradbury because people loved her personally as much as they loved her books.

"She was tremendously important initially as a children's book author, and then as she wrote meditative Christian essays, that sort of expanded her audience," he said. "She spoke exactly the way she wrote, very elegant, no nonsense, crisp, and deeply spiritual."

"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.

The brother and sister, helped by a young neighbor, Calvin, and some supernatural spirits, must pass through a time travel corridor (the "wrinkle in time") and overcome the ruling powers on a planet with a totalitarian government reminiscent of George Orwell's "1984."