The journey of a spiritual aspirant through contemplation is a direct and difficult path. The ṛṣis of yore have elaborated and elucidated this teaching , particularly in the Chāndogya Upaniṣad, of the Upadeśa Mahāvākya Tattvamasi -That Thou Art. Bhagavan Ādi Śaṅkarācārya, in his utter compassion, benevolence and unique versatility, brings forth a highest teaching enshrined in this thought provoking statement with iths word meaning (vācyārtha) and its import (lakṣyārtha) and the consequent dawning of Ahaṁ Brahmasmi in the sādhaka' s mind. Swami Chinmayananda in this commentary makes a very lucid and deep analysis of the intricate and subtle thought development of the sentence ΄That Thou Art΄. He brings out clarity into how to understand each word of the statement and arrive at the clear meaning of the Mahāvākya for us all in this beautiful dialogue between teacher and student. A great aid and blessiong to all serious sādhakas on this very subjective analysis of Self -enquiry.