Brhadaranyaka Upanishad - This book presents a lucid exposition of select portions of this Upanishad in the light of modern thought and modern needs. The Revered Swami has done this by freely drawing from contemporary scientific thought, biology, and physics, and by laying stress on the relevance of Vedantic ideas to these areas of modern thought.
This is the great lesson that we are here to learn through myriads of births and heavens and hells -- that there is nothing to be asked for, desired for, beyond one's spiritual Self (atman).
-Swami Vivekananda