The Upanisads which contain lofty philosophical teachings of the great seers constitute the most authoritative sourcebook for the Vedanta system of philosophy. However, there is no unanimity among the ancient exponents of Vedanta regarding the nature of the philosophy adumbrated in the Upanisads. Dr. Chari's scholarly work attempts to make a dispassionate study of the philosophical passages of the fourteen Principal Upanisads by giving due consideration to not only the comments of Samkara, Ramanuja and Madhva, but more importantly, the authoritative views of Badarayana as enshrined in his classic Vedantasutras. In the first part of the book, he presents the important passages of the Upanisads along with English rendering indicating the variations in the interpretation by the three commentators and also discusses their philosophical implications with reference to the Vedanta doctrines developed in the post-Upanisadic period.

In the second part he has attempted to consolidate the variety of philosophical thoughts scattered all over the Upansads period into coherent doctrines under five broad subjects: Brahman, jivatman, jagat, sadhana, and parama-purusartha. In the final chapter he conclusively establishes on the basis of an objective evaluation of the views of the commentators that the Upanisads do not support the main tenets of Advaita such as the concept of Nirvisesa Brahman, the identity of jivatman and Brahman, the phenomenal character of the jagat and the doctrine of maya. The author maintains with sufficient textual support that the nature of the philosophy advocated by the Upanisads is Theistic Monism. This book, which is the first of its kind, presents an authentic and comprehensive exposition of the philosophy of the Upansids.