By the time Theodor Seuss Geisel died in 1991, he had published 46 children's books, including many that are considered classics of children's literature, including The Cat in the Hat, Oh, The Places You'll Go, Green Eggs and Ham, How the Grinch Stole Christmas, and many others. During his life, Dr. Seuss sold hundreds of millions of books, and saw several of his works adapted for television and for the theater. His popularity during his life was inestimable; his name was synonymous with popular children's literature. In this respect, it would difficult to suggest that he has become more popular in death than he was in life. If, however, an author's success or popularity is measured in terms of the number of volumes published under his or her name but written after his or her death by other authors, then Dr. Seuss could be considered to be more popular today than during his lifetime. Numerous "Dr. Seuss" children's books continue to be published decades after his death by authors paying homage to the "master's" legacy. Every year, more books inspired by Dr. Seuss and including his name above the title are published, yet were written by other authors. These books are sanctioned by the late author's publisher and estate in recognition of Geisel's enduring legacy. In this respect, it is possible to suggest that his importance and popularity have actually increased since his death.
Geisel believed firmly that children should not be talked down to in the tradition of the children's books that preceded his publications. He understood the young mind and how to inspire children while teaching them important lessons as well as reading skills. His contributions to the intellectual and emotional development of children remain highly respected.