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.
Learn to feel yourself in other bodies, to know that we are all one. Throw all other nonsense to the winds. Spit out your actions, good or bad, and never think of them again. What is done is done. Throw off superstition. Have no weakness even in the face of death. Do not repent, do not brood over past deeds. Be aazaad (free).
-Swami Vivekananda