Draft is a series about the art and craft of writing.

I gave birth to twins a little more than a year ago, and at the baby showers we received many books: colorful board books, big illustrated books, collections of Sandra Boynton and nursery rhymes and Dr. Seuss, but none multiple times except this one: a board book “Goodnight Moon,” a flimsy “Goodnight Moon,” a large lap book “Goodnight Moon,” and an anthology by the book’s author, Margaret Wise Brown. Of course, I thought. It’s that one that says good night a lot. I figured I’d read it before, just a story of going around the room saying good night to stuff, and I thought it was popular as a gift because it’s so appropriate for bedtime and everybody wants babies to sleep.

But, when I first sat down with the babies, on the bed, nestled into pillows, beginning a sleep routine as recommended by their doctor, I pulled out the big lap book and read it aloud, and by Page 2, it was clear to me that for whatever reason, I had never read this one before. The babies listened in their sleepy baby way, and as the pages turned, I felt a growing excitement — a literary excitement. Not what I expected from this moment. But I was struck and stunned, as I have been before, by a classic sneaking up on me and, in an instant, earning yet again another fan.

It also seemed to me to be an immediately useful writing tool.

“Goodnight Moon” does two things right away: It sets up a world and then it subverts its own rules even as it follows them. It works like a sonata of sorts, but, like a good version of the form, it does not follow a wholly predictable structure. Many children’s books do, particularly for this age, as kids love repetition and the books supply it. They often end as we expect, with a circling back to the start, and a fun twist. This is satisfying but it can be forgettable. Kids — people — also love depth and surprise, and “Goodnight Moon” offers both. Here’s what I think it does that is so radical and illuminating for writers of all kinds, poets and fiction writers and more.

First, Brown sets up her terms. We look around the room and learn about it and “meet” all the items in question. The language is direct and clear and the rhythm is just right. The telephone, which we never revisit, is aurally perfect. “In the great green room/ There was a telephone/ And a red balloon.”

After we meet the old lady whispering “hush,” there is a pause built into the page turn, and the movement begins officially. The title kicks into play. We begin with “Goodnight room” and the pacing slows: the words are fewer, or at least they seem fewer. The cello, I’d say, begins. But even though we are now revisiting the items we’ve met, we meet new things too, right away. We hadn’t greeted the moon earlier, but here it is. Not only that, but Brown allows us to hear of two moons, the real and the virtual, and not to worry about any varied rhyming scheme. When I Googled “Goodnight Moon masterpiece,” I came upon a blog post by a reader who was irritated by the moon/moon repetition I had loved. Because they are such different moons! But that post was a reminder of the gentle risk Brown takes there. After the moons, we go through the whole room and our love of repetition is satisfied and we can track the little mouse and see the lights dimming in the illustrations. The page turns are beautifully paced and quite slow.

What a surprise, then, to find that there is a blank page with “Goodnight nobody” out of nowhere, sharing a spread with “Goodnight mush.” What a surprise, then, that the story does not end with the old lady whispering “hush” but goes out the window into the night.

Most picture books would close with that old lady — that’s the balanced choice. But we see the stars and feel the air — we’ve been sure we’re staying in but now we’re floating out. Why? And then back in for the ending of “Goodnight noises everywhere.” This, the last page? At first, I looked for another page — why end here? Isn’t it a little abrupt? But (after a few more readings), isn’t it also the way for us to close our eyes metaphorically with the bunny and be in that state right before slipping off to sleep, that magical drifting moment after floating out with the stars and the air, when we only hear noises and next is sleep? The story has moved so close to the bunny as to become an experiential mirror of his drift and fall. How much deeper and more elegant that is than the neat symmetry we might expect.

For writers, this is all such a useful reminder. Yes, move around in a structure. But also float out of that structure. “Goodnight nobody” is an author’s inspired moment that is inexplicable and moving and creates an unknown that lingers. How wonderful that this oddly compassionate moment, where even nobody gets a good night, shows up in the picture book that is the most popular! There is no template, ever. When writing, how do we allow those moments of impulse, of surprise? How do we not censor that kind of leap? (I’d argue for following tangents — for not feeling bound to the topic at hand.) And when to end a story or poem or novel or essay? It’s one of the most common questions at readings: “How do you know when it’s done?”

How did Brown know? On some level, it had to have been a felt ending, a note she hit that must have seemed right and took confidence and daring to pull off. The reader has time to linger with that end and accept it — it’s not the obvious closing note of the music, it’s not the fully resolved major chord. But she trusted it. How something ends is so much about a writer training her own instinct and her own sense of that note.

The babies are 14 months old now and I’ve already read the book probably a hundred times — but these unexpected choices of hers are the ones that keep my interest. I think I have a whole lot of rounds of the book to go, but I feel sure I will never crack open the meaning of “Goodnight nobody,” and moments like that make rereading a genuine joy.

Aimee Bender is the author, most recently, of the novel “The Color Master.”