The great author Nora Ephron, not long before she died, published a list of “What I Wish I’d Known,” one of the essays in her book, “I Feel Bad About My Neck.” Among the things she wished she’d known:

  • Buy, don’t rent.
  • The plane is not going to crash.
  • Write everything down.
  • Keep a journal.

When the famed nun and author Joan Chittister offered the same advice — on journals, at least — I took notice. Journaling is an age-old and tremendously effective spiritual tool, she said.

Look around. It seems like half the saints and near-saints wrote them. There’s Trappist Monk Thomas Merton’s “Secular Journal,” “Asian Journal,” “Woods, Shore, and Desert” and his “essential journals” that others compiled for him.

Catholic priests Henri Nouwen (“The Road to Daybreak”) and Andrew Greeley (“Love Affair: A Prayer Journal”) both published journals. So did C.S. Lewis.

Flannery O’Connor’s “A Prayer Journal” became a book two years ago, a half-century after her death at age 39. Mostly it contains letters that begin “Dear God” and reveal the then-20-year-old’s struggle to reconcile deep faith with artistic ambition and the art world’s disdain of organized religion:

I would like to be intelligently holy. I want to be the best artist I can possibly be — under God.

Millions have read Anne Lamott’s “Operating Instructions: A Journal of My Son’s First Year.” Lamott, a struggling single mother and recovering alcoholic, was determined to keep her baby safe from the “craziness I have in my life.” She named him Samuel, which means “God has heard.” Wrote Lamott: “God gave me the one thing that’s ever worked in my life.”

Chittister, an ardent journal keeper herself, called journals “the x-rays of our souls,” in an online Spirituality & Practice retreat last month. When honest and authentic, she said, they expose and reveal us to ourselves. “They refuse to let us hide from ourselves.”

But journals are not memoirs or diaries with dates and times and recollections of events. They are, instead, intimate records and reactions to ideas, our lives in prayer, challenges at work and at home. Over time, they help us see what weighs on us, scares us, gives us joy. They reveal what themes rise up repeatedly, like the tapes that run nonstop in our heads. Journaling can help us move beyond those tapes, she said, and give us perspective and encouragement when our journey seems stalled. We reread them and understand: We are not actually stuck today where we were stuck yesterday, or last year.

Chittister is a fan of poet and memoirist May Sarton’s “Journal of a Solitude,” bleak though it can be:

I woke in tears this morning. I wonder whether it is possible at nearly sixty to change oneself radically. Can I learn to control resentment and hostility, the ambivalence, born somewhere far below the conscious level? If I cannot, I shall lose the person I love.

She also likes Esther “Etty” Hillesum for her ability to find light in unbearable darkness. Hillesum began her journal a year before Anne Frank began her famous diary. Both would die in Nazi concentration camps and have their work published posthumously. Hillesum’s journal, “An Interrupted Life,” has lines like this:

Ultimately, we have just one moral duty: to reclaim large areas of peace in ourselves, more and more peace, and to reflect it towards others. And the more peace there is in us, the more peace there will be in our troubled world.

And this:

Despite everything, life is full of beauty and meaning.

Few of us can match such prose. But that’s not the point, said Chittister and the many journaling advice gurus who seem almost as plentiful now as journal writers themselves. Oft repeated advice: Don’t worry about prose, spelling, grammar, sentence structure. Worry instead about a deep dive, thinking hard and truthfully about who you are behind the self you offer the world.

Chittister talked about different journal exercises. There’s the Spiritual Rorschach journal, for example: studying different paintings or poems or pieces of scripture and writing down what they mean to you in that moment. There’s the Question and Answer journal. She took a quote from Teresa of Avila: “The things of the soul must always be considered as plentiful, spacious, and large.” Then Chittister asked herself, “But what are the things of the soul?” She answered with an ever-increasing list.

Helen Cepero in “Journaling As A Spiritual Practice,” offers practical considerations. Decide where you’ll journal. At the coffeehouse to escape the family? Or in the hours before dawn when they’re still asleep? What do you want to journal in? Computers are not generally recommended. Better to write longhand, perhaps in a spiral notebook or on loose-leaf paper. Cepero likes those mottled black and white composition books. Maybe you’ll splurge on those $25 soft Italian leather journals sold at fancy stationery stores. Cepero also asks how you’d feel were someone to read your most vulnerable thoughts. Maybe you don’t care. Or maybe it’s time for a wall safe.

Cepero, too, offers exercises to begin your journal. “Choose an object you’ve had for a least six months and tell its story in the context of your life,” she says. A ticket stub, perhaps, or an old tattered sweater. Or close your eyes and imagine looking through a doorway of your childhood home. It could be the kitchen, the family room, your parents’ bedroom, your own. Record in detail everything you see, hear, smell. The colors of the paint, the wallpaper, the bedspreads; the smell of perfume bottles or a big pot simmering on the stove. Remember the light coming in the windows, whom you see, who is missing. Your mother? Father? Then record what you feel. Longing? Anger? Disappointment? A bittersweet joy?

These exercises may seem more about self-indulgent navel-gazing than deepening your life in the spirit. Yet more than 500 years ago, before journaling tips were all over the Internet, the famed theologian John Calvin explained well why journaling can do just that. Because “there is no deep knowledge of God without a deep knowledge of self,” he said, “and no deep knowing of self without a deep knowing of God.”