7. Many of his biggest books were war-related allegories.
For example, Horton Hears A Who is not really about a big ol' pachiderm hearing voices, but rather America's relationship with post-war Japan. After witnessing the Hiroshima devastation firsthand on a visit, he recognized just how much the country would have to depend on the U.S.A to recover. Pretty dark, huh?
8. He had a book pulled from shelves.
Published in the thick of the Cold War, The Butter Battle was a thinly veiled eye-for-an-eye parable about the nuclear arms race between the U.S. and Russia. It was actually banned by several public libraries at the time due to its critical stance on mutually assured destruction.