I am a qualified counsellor and hypnotherapist, and a member of the British Association of Counsellors and Psychotherapist (BACP) and The National Hypnotherapy Society.
Hypnosis is not sleep but a trance like state you are fully aware of what is going on around you and are able to respond to requests either verbally or by some other signal.
A trance state is achieved by deep relaxation of both the mind and the body using guided concentration. When this is achieved the boundary between the conscious and the unconscious minds begins to blur and then the unconscious becomes open to receiving new messages. This is when I will deliver the new messages (the therapy) that we have previously been discussed and agreed.
A person who does not want to be hypnotised will not be hypnotised. You cannot be induced into saying or behaving in a way that is not acceptable to the person. Therefore hypnosis and hypnotherapy is not mind control.
Hypnosis can be better described as an altered state of consciousness featuring a process in which you choose to see only what is relevant to the task in hand and so blocking everything else out.