This is a powerful lecture delivered by Swami Vivekananda in San Francisco in 1900.It is one of the best books delineating, in brief, the fundamentals of Vedanta in a lucid, authoritative and candid tone.
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