The Upanishads are sacred Hindu scriptures composed between 800-500 BCE that discuss the ultimate nature of reality. They teach that [1] Brahman is the single, eternal, unchanging reality beneath the illusion of multiplicity. Atman, the true self, is identical to Brahman. However, due to [2] avidya or ignorance, humans experience [3] samsara, the cycle of rebirth governed by [4] karma. The goal is to attain [5] moksha or liberation from samsara through enlightenment of the identity of Atman and Brahman.