Since ancient times, philosophers and scholars have attempted to study and analyse the profound thoughts of the Upanishads in order to unravel their true meaning. The lectures presented here are a fresh analysis of the Upanishadic thinking with respect to reality, knowledge and consciousness. Prof. Puligandla here attempts to reveal the central Upanishadic insights and the significance of the observations to modern scientific thought. He comes up with some important ideas on the nature of the ultimate reality, compatibility of science, religion and philosophy, and the Upanishadic teaching vis-a-vis modern science. He also successfully dispels crucial misunderstandings of Shankara’s philosophy and that of Nagarjuna. The speciality of the book is the author’s novel interpretation of mysticism as an effective instrument of Brahma jnana or knowledge of Reality. In a bold and intellectually stimulating presentation, Prof. Puligandla shows that the mysticism of the Indian tradition, far from being illogical or irrational, is meant to awaken and inspire the seeker’s mind for the quest of the ultimate reality. Such knowledge even transcends all forms of catogorial knowledge. This work is an extremely absorbing scholarly masterpiece characterized by a unique understanding of Upanishadic thought. Its lively yet analytical discussion of the Upanishads would present a new perspective to serious scholars of philosophy.