the truism is not so true

I have heard that you can't judge a book by its cover. I do not believe that it is true. This:
may be a perfectly fine book. When I heard about it, I seriously considered reading it. However, once I saw it in person, I knew that I would never read it. Why? Because of this author photo:
which makes me want to scream. This woman is clearly, as my office-mate put it, "the queen of the dorks." I just don't want to encourage that.