The Kaushitaki Upanishad, a sacred text within the Rigveda, is a foundational work of early Vedantic thought. It explores profound philosophical concepts, particularly the journey of the soul after death and the importance of “true knowledge” (vidya) in achieving liberation (moksha). The text emphasizes that rituals are most effective when performed with a deep understanding of their meaning, and it asserts the unity of the individual self (Atman) and the ultimate reality (Brahman).