This bright, beloved children's classic about an insatiable caterpillar has been collecting awards since it was first published in 1969. Here are a few things you might not know about it.

1. The bright colors of this book, and other Eric Carle books, contrast a dark period in his childhood.

Carle was born in Syracuse, N.Y., but when he was 6, he and his family returned to their native Stuttgart, Germany. It was 1935—precisely the wrong time to move back to Europe. World War II cast a bleak pallor of violence and loss over Carle’s childhood. His father was drafted into the German army and was captured by the Russians, and was away from the family for 8 years. When he returned, he wasn't the warm, encouraging paternal figure the then-18-year-old Carle remembered from before the war, but a distant and broken man.

The author has since speculated that he was drawn to the chunky, vibrant colors of painted tissue paper collage in part as reaction to the grimness of his childhood. "It may be psychobabble but I sometimes think I rehash that period of my life in my books,” he told The Guardian.

2. A brave art teacher introduced Carle to vibrancy that would later define his work.

Herr Kraus, Carle’s high school art teacher, recognized his young pupil’s potential and risked his livelihood for the opportunity to foster it. Flouting the rigorous policing of Nazi Germany, Kraus invited Carle to his home to see banned expressionist art, showing him reproductions of works by Paul Klee, Henri Matisse, and Pablo Picasso.

"I didn't have the slightest idea that something like that existed, because I was used to art being flag-waving, gun-toting Aryans—super-realistic Aryan farmers, the women with their brute arms,” he's said.

3. The hungry caterpillar was originally a bookworm.

The war didn't exactly endear Carle to Europe, and he longed to return to America. As a young adult, he moved back to New York and got a job as a graphic designer working in advertising. After briefly getting sent back to Germany when he was drafted by the United States Army, Carle returned to the U.S. and took a job at an ad agency, where he got the inspiration for his future classic.

"I wasn't thinking of books or anything like that," he said. "I didn't have anything to do, so I took a stack of paper and a hole-punch and I playfully punched holes ... then I looked at them. Straight away I thought of a book worm."

He pitched the idea of A Week With Willi Worm to his editor Ann Beneduce. But she was worried about the unappealing protagonist. The story goes that the pair sat around trying to think of something more engaging until, at the same instant, Ann said, "Caterpillar!" and Carle said, "Butterfly!"

4. The book’s playful design proved tricky to manufacture.

Although Carle was convinced to ditch the bookworm idea, the holes stuck, becoming the eaten-through portions of the various food items that the caterpillar devours. This distinguishing feature is part of what has made the book stand out for over 45 years—but it also almost thwarted production. The publisher failed to find a printer in the United States that could economically manufacture a book with so many die cuts, but was ultimately able to locate a suitable printer in Japan that took on the project.

5. It has been interpreted as a Catholic parable ...

Because of the central transformation—which features the caterpillar retreating into a cocoon only to reemerge a butterfly—the book is often thought to have religious undertones. It's a popular addition to sermons and Sunday school curriculums.

6. … And a support for capitalism.

But not everyone thinks that the hungry caterpillar’s transformation is biblically-inspired. A young East German librarian once told Carle that she opposed the book on the basis of capitalism: "She said, 'This book would never have been published here. The caterpillar represents a capitalist. He bites into every fruit, just takes one bite and he moves on, getting fatter and fatter. He's exploiting everything.'"

7. Former President George W. Bush was a big fan of the book.

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When he made stops at schools along the campaign trail, Bush would only read The Very Hungry Caterpillar. "If teachers have put out other books his advance team will clear them," Nick Clark, the former chief curator and founding director of the Eric Carle Museum of Picture Book Art, told The Guardian.

And that's despite the fact that his affection for the book earned Bush a round of public mockery earlier in his political career. In 1999, then-governor Bush listed Eric Carle’s picture book as one of his favorite books from childhood. The only problem? He was almost 23 when The Very Hungry Caterpillar came out. The media lampooned Bush for his childish taste in literature, but it evidentially didn’t squash his spirit for the book.

8. Carle thinks the sparseness of the book is part of its appeal.

All children’s books are pared down, but The Very Hungry Caterpillar is especially so: There's very little deviation from the pattern, and the text is lacking in poetics and rhyme. But Carle says this is intentional, comparing the clean efficient nature of the book to his grandfather’s work on car engines, building "[b]eautiful parts for Porsche cars.”

In fact, a desire to imbue the world of children’s literature with this pared down style was what first motivated him to try his hand at writing. “Way back, when I was in advertising, someone asked me to illustrate what they called ‘educational material,’ and I thought it was pretty awful,” Carle said in 2009. “They put too much on the pages—I would say 32 good ideas on one page makes a terrible book. Then Bill Martin Jr. asked if I’d illustrate his book Brown Bear, Brown Bear, What Do You See? It turned me on—the simplicity of the text, the rhythm of that book. I learned from Bill: you take one idea and spread it over 32 pages.”

9. There was a terrible TV version ...

In 1993, the United Kingdom production company The Illuminated Film Company released a television version of The Very Hungry Caterpillar and several other of Carle’s stories as The World of Eric Carle. The shorts went to DVD under the title The Very Hungry Caterpillar & Other Stories and are still available for download on iTunes or Amazon. You might want to think twice before purchasing, though: The author himself described the DVD set as "awful. God-awful. I'm ashamed of it."

10. ... And a video game.

In 2010, CYBIRD Co., Ltd. debuted an educational video game based on The Very Hungry Caterpillar. Curiously, even though the book itself serves as an early tool for teaching counting, the video game, The Very Hungry Caterpillar's ABCs, focuses on language basics.

11. Carle has an idea of what makes the book so popular, but it’s purely incidental.

Asked why he thinks The Very Hungry Caterpillar has enjoyed so much success, Carle had this to say:

My guess is it’s a book of hope. That you, an insignificant, ugly little caterpillar can grow up and eventually unfold your talent, and fly into the world. As a child, you can feel small and helpless and wonder if you’ll ever grow up. So that might be part of its success. But those thoughts came afterwards, a kind of psychobabble in retrospect. I didn’t start out and say: 'I want to make a really meaningful book.'

12. There was a Google doodle for its 40th birthday ...

In 2009, on the 40th anniversary of the publication of The Very Hungry Caterpillar, Google celebrated the book with an Eric Carle-style doodle on the homepage.

13. ... And a healthy eating campaign pegged to the book.

Sure, if you eat every day like the titular caterpillar does on Saturday (one piece of chocolate cake, one ice cream cone, one pickle, one slice of Swiss cheese, one slice of salami, one lollipop, one piece of cherry pie, one sausage, one cupcake, and one slice of watermelon), you might end up with more than just a stomach ache, but the American Academy of Pediatrics thought that the bright and appealing treatment of produce during the rest of the week could be a positive influence on children’s diets. In 2011, the group partnered with a charity associated with former President Bill Clinton to send more than 17,000 pediatricians special copies of the book, along with growth charts and parent handouts on healthy eating.

14. It has been translated into 62 languages ...

Including Yiddish, Urdu, Ukrainian, Tamil, Somali, Panjabi, Luxembourgish, Latvian, Icelandic, Gaelic, Frysian, Catalan, and Aramaic.

15. ... And it's incredibly successful.

There’s a copy of The Very Hungry Caterpillar sold somewhere in the world every minute, totaling well over 30 million copies by now. "It is one of our most successful books of all time,” Francesca Dow, managing director of Puffin Books, has told The Guardian. "It's a publisher's dream and we are very lucky to have it."

Even other authors recognize the preeminence of Eric Carle's pared-down masterpiece. "The Very Hungry Caterpillar is one of the pillars of children's culture," says fellow children’s book author Ted Dewan. "It's almost like talking about how great the Beatles were. It's beyond reproach."