Letters on Yoga is a collection of letters written by Sri Aurobindo on the philosophical and psychological foundations of Integral Yoga. He wrote the letters between 1927 and 1950 to his disciples, in response to their queries.
Excerpts from the book follow:
Consciousness
Consciousness is a fundamental thing, it is the fundamental thing in existence – it is the energy, the action, the movement of consciousness that creates the universe and all that is in it – not only the macrocosm, but the microcosm is nothing but consciousness arranging itself.
This is the crucial point in the question, what is consciousness, whether it is a temporary phenomenon of Nature or a reality in itself fundamental to existence.
Men do not know themselves and have not learned to distinguish the different parts of their being. […] It is part of the foundation of Yoga to become conscious of the great complexity of our nature, see the different forces that move it and get over it a control of directing knowledge.
The Riddle of this World
This is an unideal and unsatisfactory world, strongly marked with the stamp of inadequacy, suffering, evil. […] why should evil and suffering ever have been there? […] It is not, as some religions suppose, a supra-cosmic, arbitrary, personal Deity himself altogether uninvolved in the fall who has imposed evil and suffering on creatures made capriciously by his fiat. The Divine we know is an Infinite Being in whose infinite manifestation these things have come – it is the Divine itself that is here, behind us, pervading the manifestation. […] in ourselves there is a spirit, a central presence greater than the series of surface personalities. If we find out this Divine within us, if we know ourselves as this spirit, that is our gate of deliverance and in it we can remain ourselves even in the midst of this world’s disharmonies, luminous, blissful, and free. That much is the age-old testimony of spiritual experience.
Transformation
Transformation of the body […] The inner must change before the outermost can follow.
Religion
The Divine Truth is greater than any religion or creed or scripture or idea or philosophy. I regard the spiritual history of mankind and especially of India as a constant development of a divine purpose, not a book that is closed. […] I may say that it is far from my purpose to propagate any religion new or old. I have no attachment to the past forms; what is Truth will always remain; the Truth alone matters.
Fate / Destiny
Destiny in the rigid sense applies only to the outer being so long as it lives in the Ignorance. […] But as soon as one enters the path of spiritual life, this old predetermined destiny begins to recede. Question: Can astrological truths have any influence on a sadhak? Answer: That is not the question. The question is what influence has the sadhak on the stars?
Food / Diet
Prolonged fasting may lead to an excitation of the nervous being which often brings vivid imaginations and hallucinations […] It is therefore discouraged. The rule to be followed is that laid down by the Gita which says that “Yoga is not for one who eats too much or who does not eat.”