Il Sung Na is the author-illustrator of many books for children, including A Book of Sleep; Bird, Balloon, Bear; That's My Carrot, and A Book of Babies, all of which received at least one starred review. The New York Times has praised that Il Sung "brings fresh energy to the familiar." Originally from South Korea, Il Sung studied illustration at Kingston University in London, and now lives in Kansas City with his wife, where he spends time teaching illustration courses at the Kansas City Art Institute.