Shiva-yoga is a technique of opening the third eye. The third eye is an enigmatic organ having a universal mythological history. It is the middle eye of Shiva; it is the eye of Horas of Egyptian tradition, it is the horn of the unicorn. The third eye is an organ apparently dormant but innately acquired by mankind whose awakening is the birth right of every individual. It is an organ of inner vision which embraces eternity, while the two physical eyes look before seeing neither the past nor the future.
In Yoga-Shastra the pineal gland is spoken of as the third eye, the function of which takes place through the middle of the forehead. This third eye or the pineal gland is atrophied in man;the whole process of Shiva-yoga is directed to the awakening of this dormant pineal gland. It is a rudimentary organ in most people but it is evolving though slowly. It is possible to quicken its evolution into a condition in which it can perform its function of apprehending events comprehensively to give personal access to wisdom.
– From the Teachings of Param Poojya Mahatapsvi Shri Kumarswamiji