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.
I adored her books when I was in middle school.