This is an example of a lucid dream: a dream in which you know during the dream that you are dreaming. This ability to, as it were, wake up inside a dream, prompts all sorts of interesting questions about sleep, dreams and ASCs. What does it mean to say that ‘I become conscious’ in a lucid dream? Aren’t you conscious in ordinary dreams? What are dreams anyway? Are they experiences or only stories constructed on waking up? And who is the dreamer? In this chapter we will skim over the basics of sleep and dream research, for they are well covered in many texts (e.g. Empson, 2001, Hobson, 2002, Horne, 2006) and concentrate on what ordinary dreams, as well as some more exotic kinds of dream, can tell us about consciousness.