'The Prime of Miss Jean Brodie'

I was reading this book at my in-laws house on Christmas Day. My father-in-law, whose favorite author if Clive Cussler, walks by and asks what I'm reading.

I reply.

I know he's never read it and will never read it. So what do you say in reply if you're him about me reading a book he knows nothing about?

"Ooh. That's a classic."

Thanks, dad. Can I call you dad?