Did you know you could be fired for not removing a political sticker from your car — or even having a beer after work? Lewis Maltby says it's more than possible — it's happened. His new book, Can They Do That? explores rights in the workplace.

As he tells NPR's Ari Shapiro, "Freedom of speech is protected by the First Amendment — but only where the government is concerned.

"What most Americans generally don't know is that the Constitution doesn't apply to private corporations at all."

In terms of monitoring its employees, the list of things a corporation can't do is a short one — it's basically confined to eavesdropping on a personal oral conversation, Maltby said. "Anything else is open season."