Like the unstoppable caterpillar in his most famous work, Eric Carle invested a great deal of effort into making his best-selling children’s books take flight.
“My books are not simple,” he told the Globe in 1989. “I devote my entire life to them, and I don’t do anything else. I think a lot. My books take a very long time. I may work two to three years on an idea. I start with 2,000 words, and reduce them to 20.”
Such loving labor turned him into one of the most successful children’s book authors, with more than 70 titles — including “The Very Hungry Caterpillar” — selling an estimated 170 million copies around the world in dozens of languages.
Mr. Carle, who formerly lived in the Northampton area for about three decades, died Sunday in Northampton, where he still kept a summer studio after retiring 17 years ago to North Carolina and the Florida Keys. He was 91 and the cause was kidney failure, said his son, Rolf.
“Caterpillar,” Mr. Carle’s best-known book, tells the story of a larva that, on the way to becoming a butterfly, eats and eats and eats — first various fruits, and then desserts and other food.
Holes in the pages chart the caterpillar’s tasty journey, which is punctuated by the refrain: “but he was still hungry.”
The success of the 1969 book surprised Mr. Carle as much as it delighted him.
“Children write to me and send me caterpillars all the time,” he said of his 14-page book, which is among the 10 most checked-out books in the history of the New York Public Library, The New York Times reported last year.
“Part of its success is that it represents the ugly-duckling story,” Mr. Carle said of the caterpillar who blossoms into a butterfly. “It represents hope. Children know this. They are very smart.”
The American Library Association honored Mr. Carle in 2003 with the prestigious Laura Ingalls Wilder Award, which has since been renamed the Children’s Literature Legacy Award. The honor recognizes authors, illustrators, and work that make lasting contributions to children’s literature.
The previous year, Mr. Carle and his wife, Barbara, founded the Eric Carle Museum of Picture Book Art — a 40,000-square-foot complex set on more than 7 acres in an Amherst apple orchard adjacent to Hampshire College.
“The museum is for looking and dreaming,” he once said, and the building is not just for his work.
With its three galleries, theater, art studio, libraries, and other amenities, the museum houses thousands of original objects and has exhibited the works of scores of other artists.
Current gallery exhibits include “Picture the Dream: The Story of the Civil Rights Movement through Children’s Books.” Online visitors can peruse “Asians, Everyday,” an exhibition featuring 26 artists that is designed to “celebrate our common humanity by depicting Asian Americans living their everyday lives.”
In its permanent collection, the museum also houses thousands of pieces of original art from artists such as Mr. Carle, whose field had not lent itself to preserving such material in the past.
“A generation ago, the originals were not important,” he told the Globe in 2011, when the museum had about 2,000 of his original drawings and artworks for his books. Another 1,000 originals have been lost, he estimated.
“Very often, the publisher kept them or lost them,” he said, “or the printer threw them out, or the artist threw them away.”
Mr. Carle had envisioned that entering the museum would be akin to stepping into one of his books, and that the building would welcome everyone.
“This museum is really not just for children,” he told the Globe. “We want here teachers and artists and librarians and future teachers and lovers of books and lovers of art.”
Mr. Carle was born on June 25, 1929, in Syracuse, N.Y., to Erich Carle and Johanna Oelschlager, who were German immigrants.
When Eric was 6, his mother became homesick and the family returned to his parents’ hometown of Stuttgart, Germany.
He had loved his time in Syracuse, where his artistic talent was beginning to blossom.
“Life,” he recalled in 2002, “was a large piece of paper, beautiful.”
Germany was very different. “I had to start school all over again with a teacher who was a disciplinarian,” he said. “It was small sheets of paper, hard pens, and I think I’m still trying to resolve that period through my books.”
When Mr. Carle was 10, his father was drafted into the German army. He then was captured and imprisoned in the Soviet Union, returning home years later skeletal and traumatized.
Enduring the ordeal of those years led Mr. Carle to bring “a lightness and a joy to much in his life,” Rolf said. “He wanted joy and he wanted to give joy to other people.”
After studying graphic art and typography and graduating from an academy in Stuttgart, Mr. Carle moved to the United States in 1952 with only $40 to start a new life.
He became a graphic designer for The New York Times, and then was drafted into the US Army during the Korean War. Though he hadn’t fully mastered English, he was stationed in Germany as a clerk, and asked to help translate letters, his son said.
Returning home, and initially to the Times, he became a freelance artist in the early 1960s.
His entry into children’s literature was by chance — children’s author Bill Martin Jr. spotted an advertisement Mr. Carle had created and asked him to illustrate Martin’s 1967 book “Brown Bear, Brown Bear, What Do You See?”
Moving into the field himself, Mr. Carle began publishing books, including “The Very Hungry Caterpillar” two years later.
Mr. Carle married Dorothea Wohlenberg in 1953. They had two children — Rolf, who lives in Brooklyn, N.Y., and a daughter, Cirsten, who lives in Arizona.
Mr. Carle’s first marriage ended in divorce in 1963 and his children and his sister, Christa Bareis, are his only immediate survivors.
He married Barbara Morrison, who was known as Bobbie, in 1973. When they met, she was a Montessori teacher working at the Cloisters bookshop in New York.
They initially moved to Hawley, in Western Massachusetts, where they purchased 50 acres, and later settled in Northampton.
Mrs. Carle, who received a master’s in special education from the University of Massachusetts, founded a preschool that helped integrate special needs children into mainstream classrooms. She died in 2015.
Though his success as a children’s author was beyond what he could have hoped for when he first began writing and illustrating books, Mr. Carle didn’t initially grasp how much he was touching the lives of children everywhere until mail began pouring in from across the country and around the world.
“I get their affection from letters, 10,000 a year, and it’s finally sinking in that they love me,” he told the Globe just before his museum opened in 2002. “The nice thing is that you cannot influence children. You show them a book, and they accept it or they don’t. . . . It makes me feel good to know I’m embraced by children, and not because of anybody’s taste except their own.”
Bryan Marquard can be reached at email@example.com.