Lucid dreamers are aware that they are dreaming, within the dream, and the dreams experienced in this state are sometimes remembered with unusual precision. Flying dreams can be lucid; the dreamer knows it is possible to take off from a roof or cliff top because it is a dream and the ensuing sensation may be exhilarating.   ‘Lucid’ simply means clear or rational; nine times out of ten, what causes a dream to become lucid is the sudden conscious realisation that something in it is too unlikely or downright impossible to really be happening. Bookopedia Imprint The Perfect Reference Point