Although the word hypnosis comes from the Greek word hypnos meaning "to sleep," hypnosis is not sleep at all, but rather a very deep state of physical relaxation and acute mental alertness. This state is more correctly described as a hypnotic trance.
For more on hypnosis, read on and also see my 30-minute interview conducted by Kate Blecher of Kate's Holistic Healing.
Often the conscious mind and the unconscious mind are in conflict or disagreement. For example, consciously you may want to stop smoking, but unconsciously you may still associate smoking with being macho or looking sophisticated. Or you may consciously want to eat better food and smaller portions, but unconsciously may associate eating with a positive experience like being nurtured or loved.