CAN you judge a book by its cover?
I certainly DO judge a book by its cover. It is a thousand times more likely that I will pick up a book with a shiny beautiful new cover than one with a dusty colourless cover (and there is plenty of dull brownish/greyish old books in the libraries).
However, the question is CAN we judge a book by its cover. My answer would be most certainly NOT. You can perhaps judge a book by the title or the author (especially if you have read the author before), but not solely on the basis of the cover art. There are plenty wonderful covers around, I’ve picked some and then the content was rotten (I really can’t think of an example right now). On the other hand there are brilliant stories and characters hiding behind plain, boring covers, for example the classics.