The famous sage, Ramana Maharshi, defined the whole of Vedanta in one sentence which he oft used to repeat, "Deham Naham Kohum Soham”. This is the essence of Vedanta. If you know this, not theoretically but experientially, you have known all the Upanishads and Vedanta. According to Raman Maharshi, if anybody goes deeper into the matter and asks, “If I am not the body then Who am I?”, the answer is “Soham”. He said that when one asks this question, Koham? Soham is the answer. I am not different from that Supreme Being.