Sara Teasdale - I Know the Stars lyrics

I know the stars by their names,   Aldebaran, Altair, And I know the path they take   Up heaven's broad blue stair. I know the secrets of men   By the look of their eyes, Their gray thoughts, their strange thoughts   Have made me sad and wise. But your eyes are dark to me   Though they seem to call and call— I cannot tell if you love me   Or do not love me at all. I know many things,   But the years come and go, I shall die not knowing   The thing I long to know.