Perhaps the central concern of Hindu philosophy is attaining a spiritual union with the divine. This is sometimes understood theistically and other times not. What is common in both traditions is the idea that we ourselves must find a path to union with the divine. To do this, we must first understand who (or what) we are. In the West, we often seek self-understanding through introspection and psychoanalysis to uncover an authentic identity as opposed to one that has been created for us by our family and social conditions. "Finding one's self" is about understanding our true values, true passions, or true life projects. One should contrast this self knowledge with the self knowledge that Swami Abhedananda calls upon us to discover in his book Vedanta Philosophy: Self-Knowledge (Atma-Jnana).
The self knowledge at issue here is less a question of "who am I" and more a question of "what am I." It is a more fundamental inquiry. Abhedananda begins this inquiry by examining the concepts of mind and matter (especially matter). He asserts that three relationships have been posited between these ideas: (1) that mind exists only as a product of matter (materialism), (2) that matter exists only as a product of mind (idealism), and (3) that each is dependent upon the other as two poles of a magnet (monism). Abhedananda presents a number of arguments against materialism. He goes on to simply assert that idealism is "as erroneous as the materialistic theory." His preference is for monism.
The true self or "atman" is then equated with God. This is Advaita Vedantism. By understanding that the true self is neither the ephemeral material self nor the individual mind, one comes to know that one's true self is an eternal, cosmic, universal "Soul of our souls" and that "those who do not realize this true Self, dwell in the darkness of ignorance and go through the misery and sufferings which exist in that darkness." Critical to understanding one's true self is to recognize that at the base of all experience is "prana" or the life-force which animates the world and makes all experience possible. It is "inseparable from intelligence and self consciousness." Later, Abhedananda employs the traditional analogy for the true self saying that it is like the sun, creating the possibility that all things can be visible.
Perhaps the most critical idea here is that the question that vexes the materialist and the idealist is that the relationship between the self and the world, the subject and the object, Atman and Brahman, is obscure. Abhedananda, in line with the Advaita Vedanta tradition draws the conclusion that Atman is Brahman and that recognizing this allows us to escape our suffering and become fully actualized.