Goodnight Moon is a deceptively simple children’s book that falls somewhere between a going-to-sleep narrative and a lullaby—and yet it remains one of the most universal cultural references even all these decades later. Here are a few things you might not have known about Margaret Wise Brown's sparse classic.

1. Goodnight Moon's style reflects real childhood semantics.

Brown was born in 1910 to moderately wealthy but distant and bickering parents. She and her siblings (an older sister, Roberta, and a younger brother, Benjamin) spent their childhood at various boarding schools, and despite her father's concern that education would be wasted on the girls, all three went to college. Brown attended Hollins College in Virginia, where she enjoyed the social life and athletics but struggled to find herself academically. She graduated in 1932 and moved back to New York to live with her parents, dividing her time between various sports and day jobs.

Three years later, when she was 25 and still searching for a career, Brown enrolled in Bank Street’s Cooperative School for Student Teachers. It would prove to be a life-altering experience. Founded by visionary educator Lucy Sprague Mitchell, the school's teachers, psychologists, and researchers worked in an actual nursery school to study early childhood development. The adults at Bank Street were encouraged to take copious notes on the semantics and language styles used by young children. "They tell me stories and I write them down. Amazing,” Brown wrote to her college professor and mentor, Marguerite Hearsey.

One of Bank Street's early ground-breaking revelations in children's speech patterns was Mitchell's observation that "communication is not the earliest impulse that leads to the use of language." Instead, young kids were more interested in the "rhythm, sound quality and patterns of sound." Brown certainly understood this fact. Her work at the Bank Street Writers Laboratory showed a particular flair for rhythmic language that she would later use to hypnotic effect in Goodnight Moon. “Probably she has the most consistent and genuine interest in language of the group, perhaps of all our students. Her product, though slight, always shows sensitivity to form, sound and rhythm,” Mitchell wrote in one evaluation.

2. Goodnight Moon represented a new kind of children's literature: The "here-and-now."

In the 1930s, most children's literature was still firmly stuck in the 19th century, and consisted of moralizing fables or fairytales set in faraway lands and distant ages. Then, Bank Street and Lucy Mitchell started a new tradition: The so-called "here-and-now," which featured modern, urban settings and stories that would reflect a child’s actual existence. Young children, they believed, didn't need fantasy—daily routines were still new and exciting and in need of further exploration. Goodnight Moon deals explicitly with the "here and now" of a child's bedtime—all the physical items that make up a bedroom from telephones to socks with a focus on the single, simple act of saying "goodnight."

3. Brown was a successful writer long before Goodnight Moon.

After Mitchell enlisted Brown to assist her on later editions of the anthology/textbook, The Here and Now Story Book—which had been first published in 1923 but found greater success in later editions—she recommended that Brown serve as editor of a new publishing house, launched by William Scott in 1938, dedicated to experimental children’s literature. There, Brown wielded a vast amount of influence over the literary world (and an ability to publish even her most outlandish projects—like a book bound in real rabbit fur!). She also wrote dozens of books—so many that she used multiple pen names to avoid flooding the market with releases bearing her name—that helped popularize "here-and-now" storytelling and paved the way for Goodnight Moon in 1947.

4. Goodnight Moon was written quickly and edited slowly.

In 1942, Brown's publishing house put out A Child's Good Night Book, with a repetitive structure and sleepy sentiments that foreshadowed Goodnight Moon. Several years later, in 1946, LIFE writer Bruce Bliven Jr. visited Brown at her house in Maine (which she called "The Only House"), and described her writing process this way:

The first draft of a Brown book is usually written in wild, enthusiastic haste, in lost unintelligible soft pencil on whatever scraps of paper are available; the backs of grocery bills, shopping lists, old envelopes. “I finish the rough draft in 20 minutes,” Miss Brown says, “and then I spend two years polishing." She is currently polishing 23 books more or less simultaneously.

Among the books Brown was polishing when Bliven visited her was Goodnight Moon. Bliven even accompanied Brown to one of the final editorial meetings for the book with her Harper publisher and close friend, Ursula Nordstrom, where they mostly discussed how well the pictures fit the text.

5. The illustrations feature some last-minute edits.

Brown’s close friend and frequent collaborator, Clement Hurd—who also illustrated her classic Runaway Bunny—is responsible for the stark, saturated, and slightly absurdist illustrations in Goodnight Moon. When Brown first sent the manuscript to Hurd, she included very few instructions, but did enclose a copy of Goya's Boy in Red for inspiration. Without much direction, it took Hurd three attempts to get the outlandish size and flatness of the room just as Brown imagined it. And still, there were a number of last-minute alterations: A framed photo on the great green room's wall was altered to depict a scene from The Runaway Bunny; the Cow Jumping Over the Moon’s udder was made less anatomical to avoid offending librarians; and the child and the old lady are cast as bunnies simply because Hurd proved to be better at drawing bunnies than humans.

6. The New York Public Library Rejected Goodnight Moon.

Influential NYPL children's librarian Anne Carroll Moore was perhaps the highest profile opponent to Bank Street and Brown's here-and-now style. A champion of the fairytale, Moore often butted heads with Brown, and although she had retired by the time Goodnight Moon was published, her successor, Francis Sayers, stayed true to the party line and refused to put the book on shelves. An internal review at the library accused the book of being "an unbearably sentimental piece of work." The Library finally reversed its original decision and began stocking the book in 1973—26 years after it was first published.

7. Other reviews were kinder ...

"Rhythmic, drowsy phrases are set to pictures that complement them perfectly in this new go-to-sleep book for very little children…The sound of the words, the ideas they convey and the pictures combine to lull and reassure when bedtime and darkness come," read the brief New York Times review. The New Yorker called it a "hypnotic bedtime litany."

8. ... Especially over time.

Goodnight Moon sold more than 6000 copies in its first year on the shelves, but in the years that followed, sales averaged just 1500 copies annually. Then, in the early 1950s, the book enjoyed a sudden and dramatic resurgence, selling 4000 in 1955, 8000 in 1960, and 20,000 in 1970. By 2000, total sales topped out at more than 11 million. The book, Writer's Almanac said, became a "word-of-mouth best-seller." A glowing mention in "Child Behavior"—a syndicated parental-advice column that appeared in newspapers across the U.S. in 1953—also helped. It praised the book, saying, "It captures the two-year-old so completely that it seems almost unlawful that you can hypnotize a child off to sleep as easily as you can by reading this small classic."

9. Despite writing one of the most popular children's books of all time, Brown herself never had kids.

And, in fact, never married. In 1946, Brown told Bliven, “Well, I don’t especially like children, either. At least not as a group. I won’t let anybody get away with anything just because he is little.”

It's not an entirely surprising choice for a woman who never really settled down, and took long, solo trips around Europe. But it also may have been a cheerful and cunning deflection away from an unintended absence in her life. In a letter to the Hollins College Alumnae Quarterly in 1945, Brown mocked her more traditional classmates, saying defensively, “How many children have you? I have 50 books.”

10. The royalties were left to a young neighbor.

Just a few months before she died suddenly from an embolism following emergency surgery in Nice, France, the 42-year-old Brown—who at the time was engaged to a much younger man—drafted a will. In it, she left the royalties to Goodnight Moon (and 68 other titles) to a young boy named Albert Clarke. She had befriended his mother through a colleague at Bank Street and lived near the family on East 71st Street in Manhattan. (Clarke claims Brown is his biological mother, but there's no proof that supports his assertion.) Even before Clarke started receiving his inheritance—the first payment, made when he was 21, was $75,000—he had a few run-ins with the law. Ultimately, the constant windfall from Goodnight Moon's sales funded his bad and often illegal behavior—drug possession and attempts to kidnap his own children—setting him up for a life of crime and estrangement from the rest of his family.

11. Goodnight Moon's legacy endures.

In the years since it debuted, Goodnight Moon has never been out of the press long. In 1986, Baltimore's The Sun included it on a list of the best bedtime stories, and in 1997, the Chicago Tribune called it "one of the most enduring in children's literature." In 2009, a writer for The Oregonian published an op-ed, "Why I loathe Goodnight Moon"—because his kids wouldn't stop asking him to read it over and over. Two years later, a modern parody, Goodnight iPad, was published. And just last year, the New York Times's Opinion Pages published an ode to the book extolling not just how effectively it soothes sleep into restless children, but also the subtle and searing literary value—how it "subverts its own rules even as it follows them."

Additional Source: Margaret Wise Brown: Awakened By the Moon.