The Upanisads from the concluding of the Vedas and are, therefore, called the Vedanta or the end of the Veda. The number of the Upanisads is not fixed. The collection of Upanisads translated by Darashikoh into Persian contained 50 Upanisads. The Muktika Upanisads gives a list of 108 Upanisads. There are about 112 Upanisads published by Nirnaya Sagar Press. But only ten Upanisads which were commented upon by Sankaracarya are taken to be genuine and most authoritative.
The Upanisads, which teach that life and death are only different forms of one and the same being and which aim at the release from mundane existence by the merging of the individual soul in the world soul through correct knowledge, have been hailed as the inspired utterances of the mystics for centuries. In them the whole of the later philosophy of the Indians is rooted.