Theodor Geisel (1904-1991), better known as Dr. Seuss, wrote the popular children's book The Cat in the Hat, among others.

Theodor Geisel, better known to millions of children as Dr. Seuss, brought a whimsical touch and a colorful imagination to the world of children's books. Before Geisel, juvenile books were largely pastel, predictable, and dominated by a didactic tone. Though Dr. Seuss books sometimes included morals, they sounded less like behavioral guidelines and more like, "listen to your feelings" and "take care of the environment," universal ideas that would win over the hearts of youngsters from around the world; Geisel's 47 books were translated into 20 languages and have sold more than 200 million copies. Of the ten bestselling hardcover children's books of all time, four were written by Geisel: The Cat in the Hat, Green Eggs and Ham, One Fish, Two Fish, Red Fish, Blue Fish, and Hop on Pop...