Nisargadatta Maharaj, the author of "I Am That", was a renowned spiritual teacher and philosopher from India. His teachings revolve around the concept of "I Am", which is the fundamental principle of his philosophy.

According to Nisargadatta Maharaj, the concept of "I Am" refers to the pure awareness or consciousness that is present in every living being. It is the ever-present sense of existence that is not dependent on any external factors. This sense of "I Am" is the ultimate truth and the source of all creation.

Nisargadatta Maharaj believed that the root cause of all suffering and confusion is the identification with the body and mind. He emphasized that the body and mind are temporary and constantly changing, while the "I Am" is eternal and unchanging. By identifying with the "I Am", one can transcend the limitations of the body and mind and experience a state of pure consciousness.

Nisargadatta Maharaj also stressed the importance of self-inquiry in understanding the concept of "I Am". He encouraged his followers to constantly question their sense of identity and to inquire into the nature of their true self. Through this process of self-inquiry, one can realize the true nature of the "I Am" and attain liberation from the cycle of birth and death.

Another key aspect of the concept of "I Am" according to Nisargadatta Maharaj is the idea of non-duality. He believed that the "I Am" is not separate from the ultimate reality or the divine consciousness. It is the same consciousness that exists in all beings and everything in the universe. By realizing this oneness, one can transcend the illusion of duality and experience true enlightenment.

In summary, the concept of "I Am" according to Nisargadatta Maharaj is the pure awareness or consciousness that is present in all beings and is the source of all creation. By identifying with the "I Am" and practicing self-inquiry, one can transcend the limitations of the body and mind and experience the ultimate truth of non-duality.