The Upanishads by Sri Aurobindo contains his final translations of and commentaries on the Isha and Kena, his final translations of the Mundaka and Katha Upanishads, and a commentary on part of the Taittiriya Upanishad. Upanishads are the ancient treatises on spiritual truths as envisioned by the seers, sages and rishis of the civilization of India.