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.
There is only one sin -- and that sin is weakness. When I was a boy, I read Milton's Paradise Lost. The only good man I had any respect for was Satan. The only saint is the soul who never weakens, faces everything, and determines to die game.
-Swami Vivekananda