Ezra Jack Keats (né Jacob Ezra Katz; March 11, 1916 – May 6, 1983) was an American writer and illustrator of children's books. He won the 1963 Caldecott Medal for illustrating The Snowy Day, which he also wrote. Keats wrote A Letter to Amy and Hi, Cat! but he was most famous for The Snowy Day. It is considered one of the most important American books of the 20th century.