Out of the eleven principal Upanishads that Sri Shankaracharya commented upon, this volume contains the translations of the first four Upanishads (Isha, Kena, Katha, and Taittiriya) and their commentaries by Sri Shankara. Study of these commentaries by a great philosopher-saint like Shankara is indispensable for the proper evaluation of the Vedanta philosophy. It contains the text of the Upanishads in Devanagari, a lucid and faithful translation of the text and commentary, relevant notes, reference to quotations, and an index to texts.