The present volume comprises Sri Aurobindo's final translations of and commentaries in every Upanishad or other Vedantic text he worked on.

Sri Aurobindo began translating and writing on the Upanishads around 1900 - several years before he took up yoga - and he continued this work for more than two decades. During this period his interpretation of these ancient writings underwent considerable development.

For this reason translations and commentaries done before 1910 and those he did afterwards have been placed in separate sections of this book. A third section contains incomplete and fragmentary work from both periods.