Mac Barnett is an American children's book writer best known for his advocacy of picture books. Born in California in 1982, he has established himself as a prolific author in the children's literature field. Since 2009, he has published over seventy works, including more than fifty picture books, graphic novels, essays, and short stories. Barnett currently serves as the National Ambassador for Young People's Literature for 2025-26, a role that reflects his prominence and influence in children's literature. His work has made him a notable figure in advocating for picture books as an important literary form.