When her children were young, author Madeleine L'Engle used to take them on nighttime visits to the top of Mohawk Mountain, not far from the family's 200-year-old Connecticut farmhouse.

The goal was to glimpse the mystery of God.

"If you need one image of God, then go outside on a clear night and look straight up at the stars. That's about as good as I can do," L'Engle told me, in 1989 during a two-hour interview before some Denver lectures.

The wonders of science and heavenly light are at the heart of her classic novel "A Wrinkle In Time." However, she said she knew that she needed to include some specifics to clarify her central message -- without clubbing young readers over the head.

"It's a work of fiction, not theology. I didn't write it expecting to get challenged on every last detail," she said.

However, she was willing to state one fact for the record, offering a variation on a quote she repeated through the years. Yes, she loved stargazing, she said, but ultimately, "I can understand God only as he is revealed in the Incarnation of Jesus of Nazareth.”

L'Engle died in 2007 at the age of 88, after publishing 60 works of fiction, non-fiction, drama, poetry and prayers. Her work is back in the news because of debates about Disney's $103-million version of "A Wrinkle In Time," which removed the book's religious images and biblical quotes.

At the time of the 1989 interview, L'Engle was already involved in talks about bringing "A Wrinkle In Time" to movie theaters -- a process that led to a low-budget, made-for-TV flop in 2004. That film downplayed her Christian imagery, as well.

It would be hard, explained L'Engle, to grasp this book's cosmic war between life and death, good and evil, darkness and light without two crucial passages.

A key character is Mrs. Who, who speaks only in famous quotations. She is part of a trio of mysterious characters -- guardian angels, according to L'Engle -- who help the children in the novel. To explain the power of "light," Mrs. Who quotes the Gospel of John: "The light shineth in the darkness, and the darkness comprehended it not."

Also, in a climactic word of encouragement to heroine Meg Murray, Mrs. Who quotes St. Paul's first letter to the Corinthians: "The foolishness of God is wiser than men; and the weakness of God is stronger than men. ... God hath chosen the foolish things of the world to confound the wise; and God hath chosen the weak things of the world to confound the things that are mighty."

None of the novel's Bible quotations made it into the Disney film, but there were new quotes from popular music and the musical "Hamilton."

"L'Engle's work is a highly imaginative one in which good and evil can literally be sensed and felt by the characters," said Barbara Nicolosi Harrington, a former Catholic nun who now teaches screenwriting.

These kinds of inner, spiritual realities are hard to visualize on screen, plus it's clear that the "heart of L'Engle's work is deeply Christian," she said. "Surely these themes would cause ambivalence or disgust in secular filmmakers. Now you have a recipe for the gutting of a beloved Christian classic into a weird, even creepy mess."

The novelist always knew that her work was hard to categorize, since her whole career was defined by a paradox. She was an Episcopalian from New York City, yet many of her strongest admirers were evangelical Christians. Then again, so were her fiercest critics.

The goal, said L'Engle, was to create fiction that was unmistakably Christian, while writing to an audience that included believers and unbelievers.

"I have been brought up to believe that the Gospel is to be spread, it is to be shared -- not kept for those who already have it," she said. "Well, 'Christian novels' reach Christians. They don't reach out. ... I am not a 'Christian writer.' I am a writer who is a Christian."

L'Engle laughed, before continuing.

"Now, if I am truly a Christian, then that will show in my work," he added. "If I am not truly a Christian, then that, too, is going to show in my work -- whether I want it to or not."