"Green Eggs and Ham" consists of just fifty different words and was the result of a bet between Seuss and Bennett Cerf (Dr. Seuss's publisher) that Seuss (after completing The Cat in the Hat using 225 words) could not complete an entire book using so few words. All but one word has just one syllable.
The 50 are: a, am, and, anywhere, are, be, boat, box, car, could, dark, do, eat, eggs, fox, goat, good, green, ham, here, house, I, if, in, let, like, may, me, mouse, not, on, or, rain, Sam, say, see, so, thank, that, the, them, there, they, train, tree, try, will, with, would, you.