Though American cartoonist Crockett Johnson was best known for his Barnaby comic strips, his most well-known and well-loved work just might be his beloved children’s picture book, Harold and the Purple Crayon.

You might remember the story of Harold and his crayon—the tale of a little four-year-old boy who imagines his own world with the help of just his purple crayon. It’s a very simple tale; Harold creates all of the things in his world that he doesn’t have access to at the moment. This includes a moon to walk beneath, a path to walk on, and more. He even draws himself a bed to sleep in.

The drawings are quirky and cute, reminiscent of a slightly messier, younger Charlie Brown with a bit more optimism in his head.

Harold and the Purple Crayon is the perfect tale to use in teaching kids about using their imaginations. There are so many activities to do with the book—such as distributing purple crayons during story time and inviting kids to create their own worlds, discussing the power of creation through art, or drawing further adventures for Harold—that it also makes for an incredible teaching tool. Plus, it’s just a sweet story for everyone to enjoy.

Harold has also come to life on the big screen through animated adaptations. Not only has Harold and the Purple Crayon been made into an enjoyable children’s film, but other adventures featuring the young boy—including A Picture for Harold’s Room and Harold’s Fairy Tale—have also been featured through animated films.

Later the stories were even made into an HBO series narrated by actress Sharon Stone. The series won a Daytime Emmy Award and is still available for viewing on HBO today. It has also received nominations for a Humanitas Prize and an Annie Award. The book has even inspired theatrical productions and a video game.

Johnson, whose real name was David Johnson Liesk, died of lung cancer in 1975, but his works live on today as some of the most popular children’s literature on the market. Though Harold and the Purple Crayon was written in 1955, it still appeals to a wide audience today. If you’re interested in other Johnson works, you might want to check out other books in the Harold series, as well as some of Johnson’s collaborative works with wife Ruth Krauss, such as The Happy Egg and The Carrot Seed.