About the Bookrnrn 'The Upanisads are Vedanta, a book of knowledge in a higher degree even than the Veda, but knowledge in the profounder Indian sense of the word, Jnana. And because it is only by an integral knowing of the Self that this kind of direct knowledge can be made complete, it was the Self the Vedantic sages sought to know, to live in and to be one with IT by identity. And through this endeavor, they came easily to see that the self in us is one with the Universal Self of all things and that this self again is the same as God and the Brahman, a transcendent Being or Existence; and they beheld, felt, lived in the inmost truth of man¿s inner and outer existence by the light of this one and unifying vision. The Upanisads are epic hymns of 'self-knowledge', world-knowledge and God-knowledge' in the words of Sri Aurobindo.rn rnrnrn The ontological enquiry of the 'Beingness' is the core of the Vedantic system of thought. The Vedantic system consists of the Upanisads, the Brahma-sutras (Vedanta aphorisms) and the Bhagavad-Gita. The Vedanta Aphorisms are again based on the essential content of the Upanisads. The Bhagavad-Gita also contains the essence of the philosophical teachings of the Upanisads. Thus the Upanisads constitute the basic structure on which the ontological enquiry of the Being and the Reality is based. All the Vedantins maintain that there is an essential unity threading the Upanisads together. rn rnrnrn The Upanisads mainly aim at explaining the nature of the Atman. That is why the Upanisadic philosophy is said to be 'Atman' centered. Their teaching is in line with the much later teaching of Socrates, 'Know thyself'.rn rnrnrn The philosophical survey of the thirteen earliest Upanisads in this book borrows considerably from the work 'A Constructive Survey of the Upanisadic Philosophy' by Prof. R.D.Ranade, a very well researched and creative presentation. rnrnrn Author: K.R. Paramahamsa rnrn K.R. Paramahamsa was a retired civil servant in India borne on the Indian Administrative Service. He has created the website Sri Sathya Sai Veda Pratishtan at www.vedamu.org , a repository of all the Vedic literature available in India in Devanagari and Grantha scripts. Besides, the website hosts 415 hours of Vedic chanting of ten Veda sakhas in different modes in a representative way. He is Adjunct Faculty of the Hindu University of America in Florida. He is now a resident of the Ashram of Bhagavan Sri Sathya Sai at Prasanthi Nilayam-515134, India in pursuit of spiritual upliftment.