Swami Nikhilananda's English translation of four of the major Upanishads - Katha, Isa, Kena, and Mundaka - offers a scholarly, yet readable version of the sacred texts of ancient India. The Upanishads form the foundation of the Hindu religion and describe the ultimate objective of life - the liberation of the soul from the bondage of the phenomenal world. Swami Nikhilananda's clear and insightful writing combined with notes and explanation based on the commentary of Sankaracharya, the great eighth-century philosopher and mystic of India, will help the spiritual seeker delve into the meaning of these spiritual treasures. This first of four volumes also contains an introduction with a general outline of the metaphysics and philosophy of Hinduism.