Isaavasya Upanishat is a small text forming part of Vajasaneya Samhita of Shukla Yajurveda. Swayambhuva Manu is its discoverer and the Yajna form of Vishnu is its presiding deity. Though small in size, it speaks of the core vedic philosophy in clear terms as it explains the nature of God, his omnipresence, his supremacy, how he controls everything and so on. It speaks of performance of karma as a sine-qua-non for staying away from sins. It lays a lot of emphasis on proper understanding and the disaster one could face in practicing philosophy without a proper understanding. The prayer part is very clear in explaining the attributes of God. In all, it forms a good read and a perfect guide for upaasana.

Vedic texts are subjected to various interpretations. The main streams of such interpretations are "advaita", "vishishtadvaita '' and "dvaita" spearheaded by Sri Sankaracharya, Sri Ramanujacharya and Sri Madhwacharya respectively. The intent of this book is to bring all the three versions of interpretations of this upanishad to the readers at one place to facilitate a comparative reading for the English knowing public. The original texts have been provided here "as they are", to present the authenticity and to facilitate a clarification through other sources, wherever found necessary.