Julie Markes lives with her husband, Eric Schine, and their two sons, Charlie and Nicholas, in Brooklyn, New York. Her books include Thanks For Thanksgiving; I Can't Talk Yet, But When I Do ...; Good Thing You're Not An Octopus!; Sidewalk 123; and Sidewalk.

In addition to illustrating the books about Mittens, Susan Kathleen Hartung has provided the art for numerous picture books, including One Leaf Rides the Wind by Celeste Davidson Mannis. She lives in Brooklyn, Michigan.