or just the fact that they take the time to read at all.  I always have a book that Im reading.  I don't know what that means about me, but my whole family likes to discuss and share books.  We pass them around a lot.

Sometimes a good barometer, I suppose, but not always. I try to read a wide range of material; everything from the Bible to the Marquis De Sade. What could one make out of that-- that I'm a messianic pervert?

you may learn something about someone seeing what they like to read. some people do not like to read at all. I love to read and certain topics I like than better. I guess you could learn a bit about their tastes in reading.

By what newspapers they read, then yes!
By what literature, then not necessarily. I know many an intelligent man who reads crap/nothing...

Somewhat.  But I know a (thankfully small) handful of people who buy "smart" books and read them just to quote them . . . and they completely get the concepts way wrong.  Just because you quote Sun Tzu doesn't mean you actually understand anything in "The Art of War".