The Secret ..
The benefits of hypnosis are astonishing and so are the challenges posed by critics. During the journey of development from its entertainment focused stage show form of Hypnotism to its contemporary form of Hypno Therapy. Right from the beginning, Hypnosis has remained under the scrutiny of the scientific society. In the late 1800's Dr. Franz Mesmer developed hypnosis and that's why initially it was named after him as 'Mesmerism' . 

Hypnosis was then used for resolving human problems and for anesthetic use during surgery. 

Scientists to day accept Hypnosis as means to access the subconscious mind which is generally not accessible. 

The subconscious mind controls vital functions of body like Breathing, walking and other most routine and repeated activities are governed by the subconscious mind. 

The subconscious mind is a store house of past experiences and that generates attitude and beliefs. Habits are formed and handled by the subconscious mind. 

Normally a man thinks and decides through  the conscious mind. However, the conscious mind feels handicapped when its decisions are contrary to the beliefs and attitude and habits stored in the subconscious mind. 
This is the reason, we face failure when we try to reform our habits. We take decision to quit smoking but this decision is taken by the conscious mind whereas habits are controlled by subconscious mind which is not under control of the conscious mind. This creates frustration. Same is true about difficulties we face while we try to reform our behaviour. If we have a confronting attitude stored in the subconscious mind, the decision taken by the conscious mind cannot be operative. 
The subconscious mind manipulates various information it has collected and creates dreams and innovative ideas. 

Thus, Hypnosis is very useful tool through which we can overcome the limitation of not having conscious access to the subconscious mind. During Hypnotic Trance, the conscious mind is not asleep and at the same time the subconscious mind can be explored. This makes it possible to bring the burried information and emotions out of the subconscious mind in the area of conscious mind. The wrong, negative and hurtful images and experiences stored in the subconscious mind can be modified through hypnotic suggestions during the process of trance. 

This alignment between conscious and subconscious mind can be utilized in overcoming limiting beliefs and harnessing excellent performance.