We can define lucid dreaming as a state in which the dreamer is aware that he is having a dream. Sometimes the person that is dreaming is able to take control over the dream, he can carefully select the characters and events or only to decide when this dream should stop. The dreamer can determine the way in which the dream will flow.
This phenomenon was present in the past and was known for the old civilizations. Sometimes it was used as a therapy and sometimes was explored as something supernatural appearance. This was familiar even to Aristotel who stated: ‘often when one is asleep, there is something in consciousness which declares that what then presents itself is but a dream’.