All that we are is the result of what we have thought. The mind is everything. What we think we become.
Hypnosis is an altered state of consciousness, where the conscious mind is supressed, allowing us to access the unconscious mind directly. Far from being an artificial state, it is a state we often find ourselves in; that state just before we fully wake up or fall asleep, that state that allows us to drive for many miles and then wonder how we got there, that state which allows us to suspend reality and enjoy a film. By following instructions and entering into trance, our unconscious mind will accept new ideas and messages which allow us to make changes that we are ready to make. Our unconscious mind will, though, keep us safe, letting us do what we are ready to do and stopping us from doing what we are not. Importantly, hypnosis can reinforce the messages and beliefs that we have consciously agreed to accept.
Hypnosis is just suggestibility; you see it in certain people.