Vedanta — literally "the end of the Vedas" — refers to the philosophical tradition based on the Upanishads, the concluding portions of the ancient Vedic scriptures. It is the most sophisticated and most influential of the six classical schools of Hindu philosophy, and it addresses the most fundamental questions: What is the nature of reality? What is the self? What is the relationship between the individual and the ultimate?
The central teaching of Advaita (non-dual) Vedanta — the school most associated in the West with Shankaracharya (8th century CE) and, more recently, with Ramana Maharshi and Nisargadatta Maharaj — is that there is only one reality: Brahman, pure consciousness, the ground of all being. The individual self (Atman) is not separate from Brahman — it is identical with it. The apparent separation, the sense of being a bounded individual self in a world of other selves and objects, is maya — not illusion in the sense of hallucination, but the creative power of consciousness to appear as multiplicity without ceasing to be unity.
The Pancha Kosha model is Vedanta's answer to the question: if the self is pure consciousness, why do we experience ourselves as physical beings with emotions, thoughts and limited awareness? Because pure consciousness has wrapped itself in five sheaths (koshas) — five layers of progressively denser matter that veil its own nature from itself. The spiritual path is the process of recognising what is beneath the sheaths — not by destroying them but by understanding what they are and what they are not. The sheaths are not obstacles to be removed but garments to be recognised as garments rather than as the wearer.