It's true...Dr. Seuss wrote "Green Eggs & Ham" on a bet that he couldn't write a book with 50 or fewer distinct words. In 1960 Bennett Cerf, the co-founder of Random House, made a bet with Dr. Seuss for $50 (about $382 today). Despite Dr. Seuss, a.k.a. Theodore Geisel, winning the bet by producing one of his most popular works Green Eggs and Ham using exactly 50 unique words, Cerf never paid up. Green Eggs and Ham went on to be Geisel’s best selling work.
Geisel’s first successful children’s book, Cat in the Hat, also was the result of a challenge to write a book in under a certain number of words. He was challenged to “write a story that first-graders can’t put down” and be limited to 225 distinct words from a list of 348 words that were selected from a standard first grader’s vocabulary list.
And now you know!