Because you are planning to read it and haven't? In my case, decades have elapsed between purchase and reading. And I imagine that Donald Trump can afford to pu

Because you are planning to read it and haven't? In my case, decades have elapsed between purchase and reading. And I imagine that Donald Trump can afford to purchase more books than I can. Or because your decorator thought that they looked good on a shelf? But I would question the judgment of a decorator who thought that a book of Hitler's speeches was just what the room needed.