The word 'Upanishad' in Sanskrit language means upa (near), ni (down) and shad (to sit), which can be summed up as 'to sit down near' (and receive instructions). The teacher and student or a spiritual master and his disciples setting was not always prevalent in strict sense. In some cases, it was husband answering questions about immortality to his wife or a teenage boy was being taught by Yama, Deity of Death. The teacher, in some cases were women sages and the seekers of inspiration were kings. Nonethless, the knowldge of Upanishad was passed on in this way by Rishies of yore to their disciples and to date, it withstood the terbulence of time.

Upanishads are considered as the backbone of Hinduism. Most of the Upanishads are either commentaries on or are an extension of four Vedas. The thoughts expressed inside Upanishadic cluster forms the core of Indian philosophy. One can find doctrines of Karma (action), Yoga (union), Punarjanma (rebirth), moksha (liberation), atma (soul) and brahman (super soul), inside these scriptures. Upanishads also gives valuable insight into Hindu belief system behind the creation of universe and the reasons behind its sustenance.

In the quietude of forest hermitages or ashrams situated on the banks of holy Ganges, these mystic knowledge was exchanged for centuries. It can be said that Upanishads are collection of writings representing oral transmission of such knowledge. Though Historians put the date of composition of Upanishads from around 800 - 400 B.C., the core of Upanishads survived and remain intact.

Upanishads are acknowledged as pinnacle of human wisdom.  None other scripture of that time can claim to contain such sublime and noble thoughts as found inside Upanishads. Written almost at the time of the dawn of civilization, Upanishads continues to evoke tremendous interest among literates of both, East as well as West.