Dr. Seuss is primarily known as a children's book author whose name is misspelled more often than it is spelled correctly. He also wrote some of his most successful books as responses to dares.
Dr. Seuss's most famous book is easy for small children to read, and from the outside, appears to be easy for small children to write. In fact, the Cat in the Hat was more meticulously planned than most NASA missions.
The Cat in the Hat is a classic that has endured the test of time, Mike Myers' cinematic atrocity, and hipsters wearing the cat's hat in an attempt to be ironic.
It started with a 1955 article by William Spaulding of Houghton Mifflin, called "Why Johnny Can't Read". Instead of taking the easy route ("Because Johnny is stupid.") Spaulding analyzed the state of reading material for young children and found it insufferably boring and retarded. Not only did nobody care about Dick and Jane throwing a ball, least of all small children with short attention spans, but the choice of words was haphazard - throwing in anything with one or two syllables instead of deliberately coming up with the most useful words to help kids learn.
Spaulding hooked up with Seuss and challenged him with the novel idea of writing a book with an actual story kids would want to read. If that wasn't crazy enough, he asked him to use a list of 300 words that they had come up with, targeted toward helping kids practice phonics.
Seuss thought this was insane and was attempting to politely back out of it when he glanced at the list one more time and decided he'd make a title out of the first two rhyming words he saw. They were "cat" and "hat".
Nine months of frustrating work later, he had a book that was 1702 words long with only 220 unique words, telling an interesting story, introducing an unforgettable character, and completely written in anapestic dimeter. (SOURCE)
Dr. Seuss's publisher, curious to see how far he could push the poor author, decided to bet $50 he couldn't write a book using only 50 unique words. Sure, he could probably turn out a simple, elegant bedtime reading poem like Goodnight Moon or something, but there was no way he was going to be able to write a story with multiple characters, a central conflict, events leading up to a climax, and a clearly stated but not overly preachy moral.
They do look slightly more tempting in a house, with a mouse...
As you probably know, he then wrote Green Eggs and Ham, which covers all those things (see graphic above). The publisher did not pull another dare on him after that, possibly frightened by the crazed look in Seuss's eyes when he began to bring it up.
As a member of the human race, Dr. Seuss had opinions, and some of these made their way into his books. He never wrote a book with the purpose of telling a moral because kids hated preachiness and so did he. However, he felt that any good story tended to naturally develop a moral, and that explains books like The Lorax (about environmentalism), The Butter Battle War (about the arms race), How The Grinch Stole Christmas (about the true meaning of Christmas), and Green Eggs And Ham (about how it's okay to eat food past its expiration date).
An illustration from The Butter Battle War. The catapult clearly represents ICBMs, or possibly nuclear aircraft carriers.
Like most humans, sometimes Dr. Seuss had bad opinions. During World War II, for example, he hated the Japanese and was in favor of internment camps. His general attitude toward the "Japs" - those abroad and living in America alike - is reflected here:
"But right now, when the Japs are planting their hatchets in our skulls, it seems like a hell of a time for us to smile and warble: `Brothers!' It is a rather flabby battle cry. If we want to win, we've got to kill Japs, whether it depresses John Haynes Holmes or not. We can get palsy-walsy afterward with those that are left."
Before you burn your copy of The Cat in the Hat though, there's more to the story. After the war, he visited Japan and became very concerned about whether Americans were paying enough attention to the war-ravaged country and its rebuilding needs. From these concerns, he wrote Horton Hears a Who, about paying attention to the needs of all people, "no matter how small" (or efficient). He dedicated the book to a Japanese friend.
Horton the elephant clearly represents the Republican administration of President Dwight Eisenhower, which was in charge when the book was written. The previous Horton book, Horton Hatches The Egg, was of course about the time when Eisenhower hatched an egg.