The unique feature of this Upanishad lies in this that while all the other Upanishads deal with several phases of Vedanta, such as Religion, Theology, Scholasticism, Mysticism, Metaphysics and Philosophy, this one deals exclusively with Philosophy, as defined by the most modern authorities. It deals with the three fundamental problems of Philosophy, viz. the nature of external and internal worlds, the nature of consciousness, and the meaning of causality. In short, it contains the quintessence of all the Upanishads. Here, the reader finds the highest Truth conveyed in a most explicit and an uncompromising manner. The book contains the Upanishad along with Gaudapada's Karika. The book contains a lucid english translation of the text along with Shankaracharya's commentary on it.