"William Ellsworth Spaulding, the director of the education division at Houghton Mifflin who later became its chairman, compiled a list of 348 words he felt wer

"William Ellsworth Spaulding, the director of the education division at Houghton Mifflin who later became its chairman, compiled a list of 348 words he felt were important for first-graders to recognize and asked Geisel to cut the list to 250 words and write a book using only those words. Spaulding challenged Geisel to 'bring back a book children can't put down.' Nine months later, Geisel, using 236 of the words given to him, completed The Cat in the Hat." -- Wikipedia Dr. Seuss: Language hacker