This note introduces "Advaita Vedanta" (aka Kevala Advaita or only Advaita) as the prime non-dualist tradition of the Indian subcontinent. It differs from most of the other books on the subject, both in approach and in scope. The approach is 'constructive' - the philosophical development of the tradition is discerned by applying exegetical and metaphysical criteria to the scriptures. The historiography is traced right from the archaeological protohistory to the New Vedanta of 20th century. Advaita Vedanta is interpreted here as a tradition moving away from the exclusivity of Vedic rituals to connect with other non-dualist and monist traditions. "Advaita" (non-dualism) and "Vedanta" (monist conclusions of Veda) then become general terms encompassing all non-dualist and monist thinking in the Indian sub-continent. True to this view, representative themes from Shaiva, Shakta, Shakya, Vaishnava and Sufi traditions are delineated with reference to Kevala Advaita. Advaita's new avatar - New Vedanta or Neo-Advaita - is seen as a natural outcome of the historical process including scientific revolution of the 20th century. It is posited as the new-age philosophy of monism - a spiritual metaphysics that complements science in its quest for Reality.