Joanna Cole  made science fun for millions of young readers. The author of "The Magic School Bus" series died on Sunday at age 75, Scholastic announced.

Cole's books launched a media franchise that sparked the imaginations of readers, viewers, and video game players for decades. And she wasn't done. 

Joanna Cole. Photo: Annabelle Helms

The prolific author was excited to be working on her next “Magic School Bus” adventure, according to friend and sometimes co-author Stephanie Calmenson, who posted a tribute on the Society of Children’s Book Writers and Illustrators website.

“Losing Joanna, we lose the chance to share Ms. Frizzle’s latest science adventure with children, making them laugh and helping them better understand the world they live in,” wrote Calmenson, who said that Cole was excited to start research for the next book.

“When it came to research, Joanna never cut corners,” said Calmenson. “Researching was her joy.”

Cole, who lived in Iowa, wrote more than 250 children’s books on a wide range of subjects, but she is best known for “The Magic School Bus” series, which began in 1986 and became a media franchise with 13 core books and dozens of tie-in titles that sold more than 93 million copies.

Illustrator Bruce Degen created the art for the series.

“I think for Joanna the excitement was always in the idea. What? Why? How?” Degen said in a press release from Scholastic. “And with ‘The Magic School Bus,’ it was how to explain it so that it is accurate and in a form that a kid can understand and use. And you can actually joke around while you are learning. She had a rare sense of what could be humorous.”

While many children’s book authors and illustrators never meet―and never need to―Degen said it was necessary for the series.

“Every page was so complicated we had to make decisions: how to make it work. Could it work? And we did. Together,” he said. “And we became friends. What Joanna has meant to the world, what there is in the world because of her, is well known. What she meant to me I can’t describe. Everyone who knew her, worked with her, loved her, knows what a loss it is.”