Narayana Guru (1854-1928), a much-revered philosopher-saint of South India, revisualised the essential Upanisadic thought with a freshness of perspective. Further, he applied basic aspects of his Upanisadic philosophy successfully to bring about radical social transformations. This book deals with his philosophy as discussed in his major work, Atmopadesa Satakam (One Hundred Verses of Self Instruction) but incorporates views and ideas from his other works as well. The work focuses on Narayana Guru's philosophic thought dealing with the meaning of Vedanta, the way to seek Reality, the role of the individual in life, and karma, maya, the atma's (self-)manifestation and sat-cit-ananda as the definition of the atma or Brahman and as the final goal. The various concepts are explained in relation to one another and from the viewpoint of achieving the final goal in life to present a unified thought construct that forms the core of Narayana Guru's philosophy. It also takes up the application of his Upanisadic philosophy in different disciplines like ethics and aesthetics and in practice of religion, temple-related matters and rites. The book will be particularly useful to scholars, teachers and students of Vedanta as well as all educated seekers of Reality.