This book serves as an introduction to the six systems of Hindu philosophy. Though these six systems are different in their approaches to the truth, they are unanimous as far as the final goal of humankind is concerned, which is, total eradication of suffering and attainment of state of eternal peace.
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