Jory John is the author of the picture books I Will Chomp You! and Quit Calling Me a Monster!, both illustrated by Bob Shea, and Goodnight Already! and I Love You Already!, illustrated by Benji Davies.

He is the co-author of the New York Times bestselling novel, The Terrible Two, and the bestseller All My Friends Are Dead, among many other books. He lives in San Francisco, USA.

Mac Barnett and Jon Klassen have made five books together: Sam and Dave Dig a Hole, Extra Yarn, The Wolf, the Duck and the Mouse, Triangle and this book, Square.

Jon is also the creator of the much-acclaimed Hat trilogy, which includes I Want My Hat Back, the Kate Greenaway and Caldecott Medal winner This Is Not My Hat and We Found a Hat.

They both live in California, USA, but in different cities. Jon is from Canada, Mac is not.