The Upanishads are a collection of texts which contain some of the central philosophical concepts of Hinduism, some of which are shared with Buddhism and jainism. The Upanishads are considered by Hindus to contain utterances concerning the nature of ultimate reality and describing the character of and path to human salvation (moksa or mukti).
The Upanishads are commonly referred to as Vedanta, variously interpreted to mean either the "last chapters, parts of the Veda" or "the object, the highest purpose of the Veda”. The concepts of Brahman(Ultimate Reality) and Atman (Soul, Self) are central ideas in all the Upanishads, and "Know your Atman" their thematic focus. The Upanishads are the foundation of Hindu philosophical thought and its diverse traditions. Of the Vedic corpus, they alone are widely known, and the central ideas of the Upanishads are at the spiritual core of Hindus.
THIS second volume completes the translation of the principal Upanishads to which Saṅkara appeals in his great commentary on the Vedanta-Sutras, viz.:
2. Talavakara or Kena-upanishad,
5. Vagasaneyi or Isa-upanishad,
These eleven have sometimes been called the old and genuine Upanishads, though I should be satisfied to call them the eleven classical Upanishads, or the fundamental Upanishads of the Vedanta philosophy.