I have 2 questions about the Martian Chronicles. In "The Earth Men", why did the martians think that the humans were crazy? What is the central theme of the Martian Chronicles?

The Martians didn't believe they were from Earth, but instead they believed they were Martians gone insane, hallucinating and imagining that they had come from another planet. All the way to the end they believed this, even thinking the insanity had somehow spread to them. As for themes, there are many--the dangers of nuclear war, the destruction of our environment, too much dependence on technology, intolerance of other cultures, and more.

heeroinuyashaterry:
I may be a little late, but READ THE BOOK, WILL YOU? I'm not trying to be mean. It's a great book and I guarantee you'll be glad you read it!