What is the theme in An Enemy of the People by Arthur Miller?

Freedom of speech is an important theme. Having adapted Ibsen's drama shortly after World War II ended, Miller obviously had Nazi Germany in mind when focusing on a man's attempt to tell his town important information he has discovered but is prohibited from doing so by the government. He is not allowed to print the information in the local newspaper and is banned from discussing the matter in a public forum. Peter Stockmann, the mayor of the town and Dr. Stockmann's brother, who is suppressing Dr. Stockmann's freedom of speech, tells him that the people are better off not knowing the truth.