Dr Seuss is the pen name for Theodor Seuss Geisel, an author who initially was headed for an academic career. His doodling during class prompted a fellow student to suggest he become an artist instead of a professor. Already an established author at that time, he changed his focus and worked in advertising for many years until WWII saw him producing movies for the war effort. In the latter years of the war he started to write & illustrate children's books with such appeal to children that he was commissioned to write a primer using the basic 200 vocabulary words.