Synopsis This work is a collection of some papers wherein the author has made a comparative study of the concepts like God, self, time, space, matter, substance and quality, Law of Karman etc., as found in different systems of Indian philosophy. In the view of the author, most of these concepts have not been properly explained by-the propunders themselves or have been mis-interpreted either by the followers or by the critics. In the present work, he has ventured to offer his own interpretations to unveil the real and original nature of these concepts. He has tried also to present his own observations on these concepts, which bear evidence to his original thoughts. His interpretations and observations further point to an underlying unity of thought among the different systems of Indian philosophy.