Author and cartoonist Norman Bridwell, best known for his celebrated Clifford the Big Red Dog books, passed away Dec. 12 in Martha's Vineyard, the Martha's Vineyard Times reports. He was 86.

Born in 1928 in Kokomo, Indiana, Bridwell attended art school in Indianapolis and New York City before going to work as a commercial artist. By 1962, with a wife and infant daughter to support, he set out to supplement his income by securing work as a children's book illustrator; among his portfolio pieces was a painting of what would eventually become Clifford.

"I did about 10 paintings. One was of a little girl standing under the chin of a big red dog and holding out her hand to see if it was still raining," Bridwell recalled last year to the School Library Journal. "I was rejected everywhere I went. One editor, Susan Hirschman, said that my work was too plain. She said, 'You may have to write a story, and then if they buy the story, you could do the art. She pointed to the sample of the girl and the dog and said, 'Maybe that’s a story.'”

And what a story it became. Bridwell made the big red dog even larger, and named him Clifford after his wife Norma's imaginary childhood friend (the author wanted to call him Tiny). The little girl was named for their own daughter Emily Elizabeth, with Clifford making his home on Birdwell Island, fashioned after after Martha's Vineyard (with a slight tweak of the author's surname). Bridwell completed the book within days; just three weeks after submitting the story and art, it was accepted by Scholastic Books.

"I got $1,000 for the book and I think $750 to do the art," he told SLJ.

Published in 1963, Clifford, the Big Red Dog was followed by more than 40 more, although Bridwell was convinced the first one was "just a fluke"; the last one, Clifford Makes the Team, was released in 2011. More than 60 million Clifford books are in print worldwide. The 25-foot dog has also made the leap to video, animated television and video games.

“Luck has a lot to do with it,” Bridwell said in his Scholastic biography, addressing his success. “So much of it has to do with stumbling into the right characteristics of this big red dog and situations you can use in a story.”

Bridwell, who also authored The Witch Next Door and A Tiny Family, is survived by his wife Norma and children Tim Bridwell and Emily Bridwell Merz.