Kate McMullan has collaborated with her husband Jim on many popular picture books, including I'm Brave!, I'm Fast!, I'm Big!, I'm Bad!, I'm Dirty!, and I Stink!, a New York Times Best Illustrated Book and Boston Globe-Horn Book Award Honor Book. She is also the author of As Warm as the Sun, the Geisel Honor Book Pearl and Wagner: One Funny Day, and the middle grade series Dragon Slayers' Academy and Myth-o-Mania, the Greek myths as told by Hades. She lives in New York City.

Sujean Rim is best known for her signature watercolor designs. Originally a shoe and accessory designer, Sujean has gone on to illustrate numerous picture books including Zoogie Boogie Fever! and the Birdie series. She lives with her husband in Westchester, New York.