Creativity

Why is it that my mind is most creative somewhere between this world and sleep? I am not really awake, but not dreaming. I am floating there, relaxed, with some conscious ability to direct my thinking, and I can compose my thoughts into amazing order. Everything seems so clear and precise. The words perfect. But when I wake in the morning that clarity dissipate like gold dust in running water. If I immediately break sleep's spell, I can write the thoughts down and preserve them...but sleep is such a desired, and not so easily obtainable, commodity for me.