Advaita, also known as Advaita Vedanta, is a philosophy and spiritual practice that originated in ancient India. It is based on the teachings of the Upanishads, which are a collection of sacred texts in Hinduism.

At its core, Advaita means "non-dual" or "not two." It is the understanding that there is only one ultimate reality, often referred to as Brahman, and that everything else is an illusion or manifestation of this ultimate reality.

Advaita teaches that the true nature of our being is not limited to our individual identities or egos, but rather it is the same as the ultimate reality of Brahman. This is often described as the realization of our true self or the understanding that we are not separate from the universe, but rather a part of it.

One of the key principles of Advaita is the concept of Maya, which refers to the illusion of the material world and our individual identities. According to Advaita, we are caught in this illusion and believe ourselves to be separate from the ultimate reality of Brahman. This separation leads to suffering and a constant search for fulfillment in external things.

The goal of Advaita is to break free from this illusion and realize our true nature as one with Brahman. This is achieved through self-inquiry and meditation, as well as guidance from a spiritual teacher or guru.

Jean Klein, the Advaita master, emphasized the importance of direct experience and understanding over intellectual knowledge. He believed that the true understanding of Advaita can only be achieved through direct experience and not just through studying texts or concepts.

In Advaita, there is no division between the spiritual and the material, as everything is seen as a manifestation of the ultimate reality. Therefore, Advaita does not reject the material world, but rather teaches that true fulfillment and happiness can only be found by realizing our true nature as one with Brahman.

In conclusion, Advaita is a philosophy and spiritual practice that teaches the non-dual nature of reality and the ultimate goal of realizing our true self as one with Brahman. It emphasizes the importance of direct experience and understanding over intellectual knowledge and sees the material world as a manifestation of the ultimate reality.