It is an ancient Sanskrit text embedded in the Yajurveda. The Upanishad contains 113 mantras or verses in six chapters. The Upanishad is one of the 33 Upanishads from Taittiriyas, and associated with the Shvetashvatara tradition within Karakas sakha of the Yajurveda. The Shvetashvatara Upanishad opens with metaphysical questions about the primal cause of all existence, its origin, its end, and what role, if any, time, nature, necessity, chance, and the spirit had as the primal cause. It then develops its answer, concluding that "the Universal Soul exists in every individual, it expresses itself in every creature, everything in the world is a projection of it, and that there is Oneness, a unity of souls in one and only Self". The text is notable for its discussion of the concept of personal god – Ishvara, and suggesting it to be a path to one's own Highest Self. The text is also notable for its multiple mentions of both Rudra and Shiva, along with other Vedic deities, and of crystallization of Shiva as a central theme.