"What's the most recent book you read?"

If you are interviewing for a marketing position, don't say you are reading a book called International Marketing Strategies. Rather, answer with a novel such as Michael Crichton books or John Grisham books. It is more realistic and shows other interests that you have.

"I just finished The Runaway Jury by John Grisham. I find all of his books very entertaining."

"I have a strong interest in World War II, so I was reading a book about Hitler. It's quite interesting to see how he grew up and what lead him to his hatred towards the Jews."

Something simple like this will be good enough.