His wife (Mama Patt) is a storyteller in Berks County (PA) and she needed a good story that was funny and true about worms. McCloskey got excited about worms and started working on the book in secret.
He used paper bags to make the book because earthworms also recycle.
To start a book: ask questions! Asked questions about worms <-- research. Incorporated some of those basic questions, especially the ones that kids are prone to ask/wonder about, into the text of the book.
If the kids can keep it to a "reasonable level of pandemonium," he would share real worms at the end of the presentation. Brought out his worm Seabiscuit (he's so fast!).
Collaborated with Francoise Mouly (art director, editor, publisher of TOON) and some pictures were cut ("They don't wear clothes") in favor of being more true than too silly/corny.
One of the more complicated ideas he cut was about Charles Darwin, who studied worms and put worms on his wife's grand piano to see if they could hear. But he realized that earthworms have sensitive skin and could feel the vibrations.
Anyone can draw/paint worms!