Answer:
My first is an insect; my second is a border; my whole puts the face in a tuneful disorder.
It holds most knowledge that has ever been said. But is not the brain, is not the head. To feathers and their masters, it's both bane and boon One empty, and one full.
When you stop and look, you can always see me. If you try to touch, you cannot feel me. I cannot move, but as you near me, I will move away from you.
Someone walked into a room and you heard a crash! Someone died. What happened?
Two bodies have I, though both joined in one. The more still I stand, the quicker I run.
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.