Answer:
I build up castles. I tear down mountains. I make some men blind. I help others to see.
You can spin, wheel and twist, but this thing can turn without moving. What is it?
White bird, featherless, flying out of paradise. Flying over sea and land. Dying in my hand.
Large as a mountain, small as a pea, Endlessly swimming in a water-less sea.
This is needed both for courage and hardcover books.
I appear in the morning. But am always there. You can never see me. Though I am everywhere. By night I am gone, though I sometimes never was. Nothing can defeat me. But I am easily gone.