About P. D. Eastman
Philip Dey Eastman (November 25, 1909 – January 7, 1986) was an American screenwriter, children's author, and illustrator. From 1936 to 1941, Eastman worked at Walt Disney Productions in assistant animation, story-sketch, and production design. In 1942, Eastman was drafted by the Army and assigned to the Signal Corps film unit, which was headed by Theodor Geisel, who later became known as Dr. Here, Eastman conducted picture planning for animated sequences in orientation and training films, and he also wrote scripts and drew storyboards for the Private Snafu series for Army-Navy Screen.
Biography source: Wikipedia. The profile adds birthday-specific historical context from the Celebs Birthday Today editorial database.