The Upanishad , a part of the Vedas, are ancient Sanskrit texts that contain some of the central philosophical concepts and ideas of Hinduism,some of which are shared with Buddhism, and Jainism.Among the most important literature in the history of Indian religions and culture, the Upanishads played an important role in the development of spiritual ideas in ancient India, marking a transition from Vedic ritualism to new ideas and institutions.

The Upanishads are commonly referred to as Vedānta. Vedanta has been interpreted as the "last chapters, parts of the Veda" and alternatively as "object, the highest purpose of the Veda". The concepts of Brahman (ultimate reality) and Ātman (soul, self) are central ideas in all of the Upanishads.

More than 200 Upanishads are known, of which the first dozen or so are the oldest and most important and are referred to as the principal or main (mukhya) Upanishads. The mukhya Upanishads are found mostly in the concluding part of the Brahmanas and Aranyakas and were, for centuries, memorized by each generation and passed down orally.though often dealing with subjects which are unconnected to the Vedas.